packaging(win): update INSTALL.md + README.md for 0.3.0

- INSTALL.md: bump the setup filename to 0.3.0; add an end-user section on text chat + sending photos/files (inline images, file chips, Save/Download, 25 MB cap, session-only); note that both ends must run the same version under "won't connect". - README.md: add a Version compatibility section (installer version tracks Cargo; a 0.x MINOR bump is a breaking wire change so everyone must reinstall; 0.3.0 can't talk to 0.2.x). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
packaging(win): bump installer version to 0.3.0
2026-06-20 23:41:22 -04:00 · 2026-06-20 23:39:30 -04:00 · 2026-06-20 23:15:06 -04:00 · 2026-06-20 23:06:12 -04:00 · 2026-06-20 23:00:51 -04:00 · 2026-06-20 22:18:50 -04:00
37 changed files with 5453 additions and 281 deletions
@@ -0,0 +1,21 @@
+# PeerSpeak Codebase Layout and Architecture Rules
+
+When working in the PeerSpeak repository, adhere to the following architectural boundaries and layout:
+
+## Code Layout
+- `src/main.rs`: The application entry point (initializes Tokio and the Iced GUI).
+- `src/app/`: The UI layer (Iced). Handles themes, views (Home, Room, Settings), and visual state. Must communicate with the core via message passing (`UiEvent`/`CoreCommand`), not direct function calls.
+- `src/core/`: The central orchestrator. 
+  - `mod.rs`: Manages the session lifecycle, ties together network and UI, and manages the async mixer tasks.
+  - `jitter.rs`: Houses the adaptive playout delay JitterBuffer and Packet Loss Concealment (PLC) logic.
+- `src/network/`: The "Dual-Plane" transport layer.
+  - `gossip.rs` (Control Plane): Built on `iroh-gossip`. Manages room rosters, verified membership, presence, and chat via cryptographically signed envelopes.
+  - `iroh_impl.rs` (Data Plane): Manages raw QUIC endpoints and peer connections. Forwards UDP voice datagrams directly to peers for minimum latency.
+- `src/audio/`: Hardware audio backends.
+  - Interfaces heavily with `cpal_impl.rs` (Windows/WASAPI) and `pipewire_impl.rs` (Linux). 
+  - **CRITICAL RULE**: The RT audio callbacks are strictly lock-free. They communicate with the async core exclusively via Single-Producer Single-Consumer (SPSC) ring buffers (`HeapRb`). Never allocate memory, log to stdout, or lock Mutexes on the RT threads.
+- `src/codec/`: Audio compression abstractions, standardizing on Opus at 48kHz mono (`opus_impl.rs`).
+
+## General Directives
+- **Security**: Audio admission is strictly derived from the verified gossip roster (S8). Never trust raw UDP sender IDs without validating against gossip.
+- **Latency**: Preserve the deterministic dialer vs acceptor logic in the QUIC layer to prevent connection loops.
@@ -0,0 +1,85 @@
+name: windows-build
+
+# Milestone M1 of the Windows port (see docs/handoff windows-migration-plan):
+# prove the tree compiles for `x86_64-pc-windows-msvc` and the unit tests pass.
+# The audio backend is the Phase 0 `CpalBackend` stub for now — this job guards
+# the *compile* boundary (cfg gating, platform deps, the PlatformAudioBackend
+# alias) so a Unix-only assumption can't sneak back in and break Windows.
+#
+# RUNNER REQUIREMENT: this needs a Windows act_runner registered with the
+# `windows-latest` label (the Linux `cargo-deny` job's container approach does
+# NOT apply here — Windows jobs run on the host, not a Linux container). If your
+# runner advertises a different label, change `runs-on` below. Until a Windows
+# runner exists this workflow is simply skipped/queued, not a failure of the
+# Linux CI.
+#
+# BUILD-HOST REQUIREMENTS (validated by the opus spike, see
+# peerspeak-windows-opus-spike.md):
+#   - MSVC C toolchain (Visual Studio Build Tools) — to compile vendored libopus.
+#   - CMake on PATH — `audiopus_sys` builds libopus from source via cmake.
+#   - CMAKE_POLICY_VERSION_MINIMUM=3.5 (set below) — the vendored libopus declares
+#     an ancient `cmake_minimum_required` that CMake >= 4.0 refuses without it.
+# GitHub-hosted `windows-latest` images ship MSVC + CMake; a self-hosted runner
+# must provide both.
+
+on:
+  push:
+    # `main` plus the in-progress port branches, so the Windows path is exercised
+    # before merge rather than only after.
+    branches: [main, "windows-port-**"]
+  pull_request:
+  # Allow manual runs from the Gitea Actions UI.
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+  # The vendored libopus (audiopus_sys -> cmake) uses cmake_minimum_required < 3.5,
+  # which CMake 4.x rejects unless this is set. See the opus spike report.
+  CMAKE_POLICY_VERSION_MINIMUM: "3.5"
+
+jobs:
+  windows-build:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust (MSVC, pinned to repo toolchain if present)
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: x86_64-pc-windows-msvc
+          components: clippy
+
+      - name: Show toolchain + build prerequisites
+        shell: bash
+        run: |
+          set -euo pipefail
+          rustc --version
+          cargo --version
+          # libopus is built from source via cmake; fail early with a clear
+          # message if the runner lacks it rather than deep in the opus build.
+          if ! command -v cmake >/dev/null 2>&1; then
+            echo "::error::cmake not found on PATH. The opus crate builds libopus from source via cmake; install CMake on this runner."
+            exit 1
+          fi
+          cmake --version
+
+      # Build on a *locked* tree so the pinned, vetted Cargo.lock versions are what
+      # get compiled — same supply-chain stance as the cargo-deny job.
+      - name: Build (all targets, msvc)
+        run: cargo build --all-targets --locked --target x86_64-pc-windows-msvc
+
+      # Unit (lib) tests only: the `transport_loopback` integration tests stand up
+      # real iroh/QUIC endpoints and need working loopback networking, which isn't
+      # guaranteed on a CI runner. Add `--tests` here once a networked Windows
+      # runner is confirmed.
+      - name: Unit tests (lib, msvc)
+        run: cargo test --lib --locked --target x86_64-pc-windows-msvc
+
+      # Informational for now (not `-D warnings`): the Windows tree may surface
+      # platform-specific lints we haven't triaged. Tighten to deny-warnings once
+      # it's clean.
+      - name: Clippy (msvc)
+        run: cargo clippy --all-targets --locked --target x86_64-pc-windows-msvc
@@ -6,3 +6,8 @@
 /packaging/peerspeak/
 /packaging/*.pkg.tar.*
 /packaging/*.log
+
+# Windows installer build artifacts (the staged exe + compiled setup.exe);
+# the .iss script and .ico are the tracked sources.
+/packaging/windows/peerspeak.exe
+/packaging/windows/output/
@@ -105,6 +105,28 @@ version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"

+[[package]]
+name = "alsa"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed7572b7ba83a31e20d1b48970ee402d2e3e0537dcfe0a3ff4d6eb7508617d43"
+dependencies = [
+ "alsa-sys",
+ "bitflags 2.11.1",
+ "cfg-if",
+ "libc",
+]
+
+[[package]]
+name = "alsa-sys"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db8fee663d06c4e303404ef5f40488a53e062f89ba8bfed81f42325aafad1527"
+dependencies = [
+ "libc",
+ "pkg-config",
+]
+
 [[package]]
 name = "android-activity"
 version = "0.6.1"
@@ -114,12 +136,12 @@ dependencies = [
 "android-properties",
 "bitflags 2.11.1",
 "cc",
- "jni",
+ "jni 0.22.4",
 "libc",
 "log",
- "ndk",
+ "ndk 0.9.0",
 "ndk-context",
- "ndk-sys",
+ "ndk-sys 0.6.0+11769913",
 "num_enum",
 "thiserror 2.0.18",
 ]
@@ -712,6 +734,12 @@ dependencies = [
 "shlex",
 ]

+[[package]]
+name = "cesu8"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d43a04d8753f35258c91f8ec639f792891f748a1edbd759cf1dcea3382ad83c"
+
 [[package]]
 name = "cexpr"
 version = "0.6.0"
@@ -1002,6 +1030,26 @@ dependencies = [
 "libm",
 ]

+[[package]]
+name = "coreaudio-rs"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "321077172d79c662f64f5071a03120748d5bb652f5231570141be24cfcd2bace"
+dependencies = [
+ "bitflags 1.3.2",
+ "core-foundation-sys",
+ "coreaudio-sys",
+]
+
+[[package]]
+name = "coreaudio-sys"
+version = "0.2.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9b4739a805a62757a83e5654fa3faabec0442666b263bb2287d5a8185bfd953"
+dependencies = [
+ "bindgen",
+]
+
 [[package]]
 name = "cosmic-text"
 version = "0.15.0"
@@ -1026,6 +1074,29 @@ dependencies = [
 "unicode-segmentation",
 ]

+[[package]]
+name = "cpal"
+version = "0.15.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "873dab07c8f743075e57f524c583985fbaf745602acbe916a01539364369a779"
+dependencies = [
+ "alsa",
+ "core-foundation-sys",
+ "coreaudio-rs",
+ "dasp_sample",
+ "jni 0.21.1",
+ "js-sys",
+ "libc",
+ "mach2",
+ "ndk 0.8.0",
+ "ndk-context",
+ "oboe",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "windows 0.54.0",
+]
+
 [[package]]
 name = "cpufeatures"
 version = "0.2.17"
@@ -1228,6 +1299,12 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "dasp_sample"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c87e182de0887fd5361989c677c4e8f5000cd9491d6d563161a8f3a5519fc7f"
+
 [[package]]
 name = "data-encoding"
 version = "2.11.0"
@@ -2227,7 +2304,7 @@ dependencies = [
 "http",
 "idna",
 "ipnet",
- "jni",
+ "jni 0.22.4",
 "rand 0.10.1",
 "rustls",
 "thiserror 2.0.18",
@@ -2247,7 +2324,7 @@ dependencies = [
 "data-encoding",
 "idna",
 "ipnet",
- "jni",
+ "jni 0.22.4",
 "once_cell",
 "prefix-trie",
 "rand 0.10.1",
@@ -2270,7 +2347,7 @@ dependencies = [
 "hickory-proto",
 "ipconfig",
 "ipnet",
- "jni",
+ "jni 0.22.4",
 "moka",
 "ndk-context",
 "once_cell",
@@ -3102,6 +3179,22 @@ version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"

+[[package]]
+name = "jni"
+version = "0.21.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a87aa2bb7d2af34197c04845522473242e1aa17c12f4935d5856491a7fb8c97"
+dependencies = [
+ "cesu8",
+ "cfg-if",
+ "combine",
+ "jni-sys 0.3.1",
+ "log",
+ "thiserror 1.0.69",
+ "walkdir",
+ "windows-sys 0.45.0",
+]
+
 [[package]]
 name = "jni"
 version = "0.22.4"
@@ -3463,6 +3556,15 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d3d25b0e0b648a86960ac23b7ad4abb9717601dec6f66c165f5b037f3f03065f"

+[[package]]
+name = "mach2"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d640282b302c0bb0a2a8e0233ead9035e3bed871f0b7e81fe4a1ec829765db44"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "malloc_buf"
 version = "0.0.6"
@@ -3596,7 +3698,7 @@ dependencies = [
 "dispatch",
 "futures-channel",
 "futures-lite",
- "jni",
+ "jni 0.22.4",
 "ndk-context",
 "objc2 0.6.4",
 "objc2-app-kit 0.3.2",
@@ -3695,6 +3797,20 @@ dependencies = [
 "unicode-ident",
 ]

+[[package]]
+name = "ndk"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2076a31b7010b17a38c01907c45b945e8f11495ee4dd588309718901b1f7a5b7"
+dependencies = [
+ "bitflags 2.11.1",
+ "jni-sys 0.3.1",
+ "log",
+ "ndk-sys 0.5.0+25.2.9519653",
+ "num_enum",
+ "thiserror 1.0.69",
+]
+
 [[package]]
 name = "ndk"
 version = "0.9.0"
@@ -3704,7 +3820,7 @@ dependencies = [
 "bitflags 2.11.1",
 "jni-sys 0.3.1",
 "log",
- "ndk-sys",
+ "ndk-sys 0.6.0+11769913",
 "num_enum",
 "raw-window-handle",
 "thiserror 1.0.69",
@@ -3716,6 +3832,15 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "27b02d87554356db9e9a873add8782d4ea6e3e58ea071a9adb9a2e8ddb884a8b"

+[[package]]
+name = "ndk-sys"
+version = "0.5.0+25.2.9519653"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8c196769dd60fd4f363e11d948139556a344e79d451aeb2fa2fd040738ef7691"
+dependencies = [
+ "jni-sys 0.3.1",
+]
+
 [[package]]
 name = "ndk-sys"
 version = "0.6.0+11769913"
@@ -4466,6 +4591,29 @@ dependencies = [
 "objc2-foundation 0.2.2",
 ]

+[[package]]
+name = "oboe"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8b61bebd49e5d43f5f8cc7ee2891c16e0f41ec7954d36bcb6c14c5e0de867fb"
+dependencies = [
+ "jni 0.21.1",
+ "ndk 0.8.0",
+ "ndk-context",
+ "num-derive",
+ "num-traits",
+ "oboe-sys",
+]
+
+[[package]]
+name = "oboe-sys"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c8bb09a4a2b1d668170cfe0a7d5bc103f8999fb316c98099b6a9939c9f2e79d"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -4594,12 +4742,13 @@ checksum = "35fb2e5f958ec131621fdd531e9fc186ed768cbe395337403ae56c17a74c68ec"

 [[package]]
 name = "peerspeak"
-version = "0.2.0"
+version = "0.3.0"
 dependencies = [
 "anyhow",
 "async-trait",
 "base64",
 "bytes",
+ "cpal",
 "dirs",
 "iced",
 "image",
@@ -5436,7 +5585,7 @@ checksum = "26d1e2536ce4f35f4846aa13bff16bd0ff40157cdb14cc056c7b14ba41233ba0"
 dependencies = [
 "core-foundation 0.10.1",
 "core-foundation-sys",
- "jni",
+ "jni 0.22.4",
 "log",
 "once_cell",
 "rustls",
@@ -5877,7 +6026,7 @@ dependencies = [
 "fastrand",
 "js-sys",
 "memmap2",
- "ndk",
+ "ndk 0.9.0",
 "objc2 0.6.4",
 "objc2-core-foundation",
 "objc2-core-graphics",
@@ -7162,7 +7311,7 @@ dependencies = [
 "log",
 "metal",
 "naga",
- "ndk-sys",
+ "ndk-sys 0.6.0+11769913",
 "objc",
 "once_cell",
 "ordered-float",
@@ -7247,6 +7396,16 @@ dependencies = [
 "thiserror 2.0.18",
 ]

+[[package]]
+name = "windows"
+version = "0.54.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9252e5725dbed82865af151df558e754e4a3c2c30818359eb17465f1346a1b49"
+dependencies = [
+ "windows-core 0.54.0",
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows"
 version = "0.58.0"
@@ -7254,7 +7413,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dd04d41d93c4992d421894c18c8b43496aa748dd4c081bac0dc93eb0489272b6"
 dependencies = [
 "windows-core 0.58.0",
- "windows-targets",
+ "windows-targets 0.52.6",
 ]

 [[package]]
@@ -7278,6 +7437,16 @@ dependencies = [
 "windows-core 0.62.2",
 ]

+[[package]]
+name = "windows-core"
+version = "0.54.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12661b9c89351d684a50a8a643ce5f608e20243b9fb84687800163429f161d65"
+dependencies = [
+ "windows-result 0.1.2",
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-core"
 version = "0.58.0"
@@ -7288,7 +7457,7 @@ dependencies = [
 "windows-interface 0.58.0",
 "windows-result 0.2.0",
 "windows-strings 0.1.0",
- "windows-targets",
+ "windows-targets 0.52.6",
 ]

 [[package]]
@@ -7386,13 +7555,22 @@ dependencies = [
 "windows-strings 0.5.1",
 ]

+[[package]]
+name = "windows-result"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e383302e8ec8515204254685643de10811af0ed97ea37210dc26fb0032647f8"
+dependencies = [
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-result"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1d1043d8214f791817bab27572aaa8af63732e11bf84aa21a45a78d6c317ae0e"
 dependencies = [
- "windows-targets",
+ "windows-targets 0.52.6",
 ]

 [[package]]
@@ -7411,7 +7589,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4cd9b125c486025df0eabcb585e62173c6c9eddcec5d117d3b6e8c30e2ee4d10"
 dependencies = [
 "windows-result 0.2.0",
- "windows-targets",
+ "windows-targets 0.52.6",
 ]

 [[package]]
@@ -7423,13 +7601,22 @@ dependencies = [
 "windows-link",
 ]

+[[package]]
+name = "windows-sys"
+version = "0.45.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75283be5efb2831d37ea142365f009c02ec203cd29a3ebecbc093d52315b66d0"
+dependencies = [
+ "windows-targets 0.42.2",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.52.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
 dependencies = [
- "windows-targets",
+ "windows-targets 0.52.6",
 ]

 [[package]]
@@ -7441,20 +7628,35 @@ dependencies = [
 "windows-link",
 ]

+[[package]]
+name = "windows-targets"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e5180c00cd44c9b1c88adb3693291f1cd93605ded80c250a75d472756b4d071"
+dependencies = [
+ "windows_aarch64_gnullvm 0.42.2",
+ "windows_aarch64_msvc 0.42.2",
+ "windows_i686_gnu 0.42.2",
+ "windows_i686_msvc 0.42.2",
+ "windows_x86_64_gnu 0.42.2",
+ "windows_x86_64_gnullvm 0.42.2",
+ "windows_x86_64_msvc 0.42.2",
+]
+
 [[package]]
 name = "windows-targets"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
 dependencies = [
- "windows_aarch64_gnullvm",
- "windows_aarch64_msvc",
- "windows_i686_gnu",
+ "windows_aarch64_gnullvm 0.52.6",
+ "windows_aarch64_msvc 0.52.6",
+ "windows_i686_gnu 0.52.6",
 "windows_i686_gnullvm",
- "windows_i686_msvc",
- "windows_x86_64_gnu",
- "windows_x86_64_gnullvm",
- "windows_x86_64_msvc",
+ "windows_i686_msvc 0.52.6",
+ "windows_x86_64_gnu 0.52.6",
+ "windows_x86_64_gnullvm 0.52.6",
+ "windows_x86_64_msvc 0.52.6",
 ]

 [[package]]
@@ -7466,18 +7668,36 @@ dependencies = [
 "windows-link",
 ]

+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "597a5118570b68bc08d8d59125332c54f1ba9d9adeedeef5b99b02ba2b0698f8"
+
 [[package]]
 name = "windows_aarch64_gnullvm"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"

+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e08e8864a60f06ef0d0ff4ba04124db8b0fb3be5776a5cd47641e942e58c4d43"
+
 [[package]]
 name = "windows_aarch64_msvc"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"

+[[package]]
+name = "windows_i686_gnu"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c61d927d8da41da96a81f029489353e68739737d3beca43145c8afec9a31a84f"
+
 [[package]]
 name = "windows_i686_gnu"
 version = "0.52.6"
@@ -7490,24 +7710,48 @@ version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"

+[[package]]
+name = "windows_i686_msvc"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44d840b6ec649f480a41c8d80f9c65108b92d89345dd94027bfe06ac444d1060"
+
 [[package]]
 name = "windows_i686_msvc"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"

+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8de912b8b8feb55c064867cf047dda097f92d51efad5b491dfb98f6bbb70cb36"
+
 [[package]]
 name = "windows_x86_64_gnu"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"

+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "26d41b46a36d453748aedef1486d5c7a85db22e56aff34643984ea85514e94a3"
+
 [[package]]
 name = "windows_x86_64_gnullvm"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"

+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9aec5da331524158c6d1a4ac0ab1541149c0b9505fde06423b02f5ef0106b9f0"
+
 [[package]]
 name = "windows_x86_64_msvc"
 version = "0.52.6"
@@ -7536,7 +7780,7 @@ dependencies = [
 "js-sys",
 "libc",
 "memmap2",
- "ndk",
+ "ndk 0.9.0",
 "objc2 0.5.2",
 "objc2-app-kit 0.2.2",
 "objc2-foundation 0.2.2",
@@ -1,6 +1,6 @@
 [package]
 name = "peerspeak"
-version = "0.2.0"
+version = "0.3.0"
 edition = "2024"
 # Application crate, not a crates.io library — refuse `cargo publish` and let
 # cargo-deny's [licenses.private] skip the missing-license check.
@@ -30,17 +30,12 @@ bytes = "1.11.1"
 dirs = "6.0.0"
 iced = { version = "0.14.0", features = ["canvas", "image"] }
 # W4 custom avatars: decode/resize an arbitrary user image (png/jpeg only to keep
-# the codec surface small) and a native file picker (xdg-portal backend, no GTK).
+# the codec surface small). The matching native file picker (`rfd`) is platform-
+# gated below — its backend differs per OS (xdg-portal on Linux, Win32 on Windows).
 image = { version = "0.25", default-features = false, features = ["png", "jpeg"] }
-rfd = { version = "0.17", default-features = false, features = ["xdg-portal"] }
 iroh = "1.0.0-rc.0"
 iroh-gossip = "0.99.0"
 opus = "0.3.1"
-# v0_3_49 exposes `Buffer::requested()` (the graph's per-cycle quantum), used by
-# the playback RT callback to fill exactly what the device asks for instead of
-# pinning the buffer to a hard-coded 1024-frame quantum (crackle on non-1024
-# hardware). The field has existed in libpipewire since 0.3.49 (2022).
-pipewire = { version = "0.9", features = ["v0_3_49"] }
 rand = "0.10.1"
 ringbuf = "0.5.0"
 serde = { version = "1.0.228", features = ["derive"] }
@@ -48,3 +43,24 @@ serde_json = "1.0.150"
 thiserror = "2.0.18"
 tokio = { version = "1.52.3", features = ["full"] }
 tokio-stream = "0.1.18"
+
+# --- Platform-specific dependencies -----------------------------------------
+# Audio and the native file-picker backends differ per OS. Everything else in the
+# app talks to the `AudioBackend` trait and the `PlatformAudioBackend` alias (see
+# `src/audio/mod.rs`), so platform selection is confined to these few lines.
+
+[target.'cfg(target_os = "linux")'.dependencies]
+# Linux audio backend. v0_3_49 exposes `Buffer::requested()` (the graph's per-cycle
+# quantum), used by the playback RT callback to fill exactly what the device asks
+# for instead of a hard-coded 1024-frame quantum (crackle on non-1024 hardware).
+# The field has existed in libpipewire since 0.3.49 (2022).
+pipewire = { version = "0.9", features = ["v0_3_49"] }
+# Native file picker via the XDG desktop portal (no GTK) on Linux.
+rfd = { version = "0.17", default-features = false, features = ["xdg-portal"] }
+
+[target.'cfg(windows)'.dependencies]
+# Native file picker using the built-in Win32 dialog backend on Windows.
+rfd = { version = "0.17", default-features = false }
+# Windows audio backend: cpal drives WASAPI for capture/playback behind the
+# AudioBackend trait (src/audio/cpal_impl.rs). The Linux counterpart is pipewire.
+cpal = "0.15"
@@ -0,0 +1,77 @@
+# PeerSpeak on Windows
+
+Current status: the Windows port cross-compiles to `x86_64-pc-windows-gnu` and the `.exe`
+launches under Wine. A real Windows/WASAPI host is still needed for the final audio-device
+checks listed below.
+
+## What works today
+
+| Area | Status |
+|---|---|
+| GUI | Iced/wgpu builds and renders under Wine. |
+| Networking | Iroh QUIC transport and gossip compile on Windows. |
+| Audio backend | `cpal` drives WASAPI capture/playback behind `AudioBackend`. |
+| Codec | Opus remains 48 kHz mono, 20 ms frames. |
+| Identity | `ring` identity generation/load is platform-neutral. |
+| Chimes | Windows uses PowerShell `System.Media.SoundPlayer` for WAV playback. |
+
+Windows paths are resolved through `dirs`:
+
+- Config: `%APPDATA%\peerspeak\config.json`
+- Identity: `%APPDATA%\peerspeak\identity.key`
+- Log: `%LOCALAPPDATA%\peerspeak\peerspeak.log`
+
+## Building
+
+### Native Windows
+
+Install MSVC Build Tools and CMake, then build normally:
+
+```powershell
+cargo build --release
+```
+
+If CMake is 4.x or newer, the vendored `opus`/`libopus` build may need:
+
+```powershell
+$env:CMAKE_POLICY_VERSION_MINIMUM = "3.5"
+cargo build --release
+```
+
+### Cross-compile from Linux
+
+The current dev path cross-compiles from an Arch environment to the GNU Windows target:
+
+```sh
+rustup target add x86_64-pc-windows-gnu
+sudo pacman -S mingw-w64-gcc cmake
+CMAKE_POLICY_VERSION_MINIMUM=3.5 cargo build --release --target x86_64-pc-windows-gnu --bin peerspeak
+```
+
+Wine is useful for launch/render smoke tests, but it is not a substitute for a real
+Windows audio-device pass. The deeper migration plan (phases, decisions, the opus build
+spike) lives in the maintainer's handoff docs, outside the repo.
+
+## First run and networking
+
+Expect a Windows Firewall prompt the first time the app opens network sockets. Allow it:
+PeerSpeak uses UDP for QUIC, plus relay traffic when direct NAT traversal is not available.
+
+The default network mode keeps the n0 relay available for NAT traversal without publishing
+presence to n0 DNS. Direct peer-to-peer paths may work when both networks allow them; relayed
+connections are expected and valid.
+
+## Known gaps
+
+| Item | Status |
+|---|---|
+| Echo cancellation | Linux-only PipeWire feature. The Windows UI shows it disabled as unavailable. |
+| Screen share | Requires a Windows `pixelpass.exe` on `PATH` or a configured override. |
+| Chimes | Now routed through Windows `SoundPlayer`; needs a real Windows host to audibly verify. |
+| Resampling/device format | Cross-compiled. cpal/WASAPI now chooses native 48 kHz when available and otherwise resamples/remaps at the device boundary; needs real Windows hardware audio verification. |
+| Device persistence | Open. WASAPI friendly names may duplicate or change across driver/profile changes. |
+| Playback pacing | Cross-compiled. The fixed playback target under WASAPI shared mode still needs real-hardware verification with `audio_probe`. |
+
+Before calling Windows support done, verify a real Windows machine can create/join a room,
+capture mic audio, hear remote audio, select devices, restart with selections preserved, and
+play notification chimes.
@@ -1,7 +1,7 @@
 # Maintainer: mollusk <jitty+lc1iz0dc@protonmail.com>
 pkgname=peerspeak-git
 _pkgname=peerspeak
-pkgver=0.1.0
+pkgver=0.2.0.r218.gcbba4b6
 pkgrel=1
 pkgdesc="Decentralized peer-to-peer voice chat (Rust/iroh/PipeWire/Opus/iced)"
 arch=('x86_64')
@@ -0,0 +1,112 @@
+# Maintainer: mollusk <jitty+lc1iz0dc@protonmail.com>
+#
+# Test-pack split package: ONE `makepkg -si` builds + installs BOTH peerspeak
+# (voice chat) and pixelpass (screen sharing) from the public gitbutter repos
+# over https. pixelpass lands on /usr/bin so peerspeak's screen-share button
+# finds it. Shared version string is derived from peerspeak's git.
+#
+# Clone this repo and build from here:
+#   git clone https://gitbutter.xyz/mollusk/peerspeak.git
+#   cd peerspeak/packaging/test-pack
+#   makepkg -si
+pkgbase=peerspeak-git
+pkgname=('peerspeak-git' 'pixelpass')
+pkgver=0.1.0
+pkgrel=1
+arch=('x86_64')
+url="https://gitbutter.xyz/mollusk/peerspeak"
+license=('custom' 'MIT' 'Apache-2.0' 'OFL-1.1')
+makedepends=('git' 'cargo' 'pkgconf')
+options=('!lto' '!debug')
+source=("peerspeak::git+https://gitbutter.xyz/mollusk/peerspeak.git"
+        "pixelpass::git+https://gitbutter.xyz/mollusk/pixelpass.git#branch=main")
+sha256sums=('SKIP'
+            'SKIP')
+
+pkgver() {
+  cd "$srcdir/peerspeak"
+  # Shared across both split packages. 0.1.0.r<commits>.g<short-sha>.
+  printf '%s.r%s.g%s' \
+    "$(awk -F'\"' '/^version =/{print $2; exit}' Cargo.toml)" \
+    "$(git rev-list --count HEAD)" \
+    "$(git rev-parse --short HEAD)"
+}
+
+prepare() {
+  # Vendor deps up front so build() can run --frozen (no surprise network).
+  export CARGO_HOME="$srcdir/cargo-home"
+  local host; host="$(rustc -vV | sed -n 's/host: //p')"
+  cd "$srcdir/peerspeak";  cargo fetch --locked --target "$host"
+  cd "$srcdir/pixelpass";  cargo fetch --locked --target "$host"
+}
+
+build() {
+  export CARGO_HOME="$srcdir/cargo-home"
+  export RUSTUP_TOOLCHAIN=stable
+  export CARGO_TARGET_DIR=target
+
+  cd "$srcdir/peerspeak"
+  cargo build --frozen --release --bin peerspeak
+
+  cd "$srcdir/pixelpass"
+  # --features gui so the .desktop launcher (pixelpass --gui) works.
+  cargo build --frozen --release --features gui
+}
+
+check() {
+  export CARGO_HOME="$srcdir/cargo-home"
+  export RUSTUP_TOOLCHAIN=stable
+  # peerspeak library unit tests only — its integration suites bind real
+  # iroh/QUIC endpoints and fail in a sandboxed/offline build environment.
+  cd "$srcdir/peerspeak"
+  cargo test --frozen --release --lib
+}
+
+package_peerspeak-git() {
+  pkgdesc="Decentralized peer-to-peer voice chat (Rust/iroh/PipeWire/Opus/iced)"
+  depends=('pipewire' 'opus')
+  optdepends=('pixelpass: screen sharing inside a room'
+              'mpv: screen-share viewer (vlc is used as a fallback)')
+  provides=('peerspeak')
+  conflicts=('peerspeak')
+  license=('custom')
+
+  cd "$srcdir/peerspeak"
+  install -Dm755 "target/release/peerspeak" "$pkgdir/usr/bin/peerspeak"
+  install -Dm644 "packaging/peerspeak.desktop" \
+    "$pkgdir/usr/share/applications/peerspeak.desktop"
+
+  # Hicolor icon theme (scalable SVG + the rendered raster sizes).
+  install -Dm644 "assets/icons/peerspeak.svg" \
+    "$pkgdir/usr/share/icons/hicolor/scalable/apps/peerspeak.svg"
+  local s
+  for s in 16 24 32 48 64 128 256 512; do
+    install -Dm644 "assets/icons/peerspeak-$s.png" \
+      "$pkgdir/usr/share/icons/hicolor/${s}x${s}/apps/peerspeak.png"
+  done
+}
+
+package_pixelpass() {
+  pkgdesc='P2P screen sharing over iroh — no port forwarding, no signup'
+  depends=('gstreamer' 'gst-plugins-base' 'gst-plugins-good' 'gst-plugins-bad'
+           'gst-libav' 'gst-plugin-va' 'libpulse' 'hicolor-icon-theme'
+           'libglvnd' 'libxkbcommon' 'wayland')
+  optdepends=('mpv: recommended stream viewer (the GUI launches mpv)'
+              'vlc: alternative stream viewer'
+              'gst-plugins-ugly: software x264 encoding for `pixelpass --no-hwencode`'
+              'gst-plugin-pipewire: screen capture on Wayland sessions'
+              'xorg-xwininfo: share a single window on X11 (`pixelpass --window`)')
+  license=('MIT' 'Apache-2.0' 'OFL-1.1')
+
+  cd "$srcdir/pixelpass"
+  install -Dm0755 "target/release/pixelpass" "$pkgdir/usr/bin/pixelpass"
+  install -Dm0644 assets/pixelpass.desktop \
+    "$pkgdir/usr/share/applications/pixelpass.desktop"
+  install -Dm0644 assets/pixelpass.svg \
+    "$pkgdir/usr/share/icons/hicolor/scalable/apps/pixelpass.svg"
+  install -Dm0644 README.md "$pkgdir/usr/share/doc/pixelpass/README.md"
+  install -Dm0644 LICENSE-MIT "$pkgdir/usr/share/licenses/pixelpass/LICENSE-MIT"
+  install -Dm0644 LICENSE-APACHE "$pkgdir/usr/share/licenses/pixelpass/LICENSE-APACHE"
+  install -Dm0644 assets/NotoSans-OFL.txt \
+    "$pkgdir/usr/share/licenses/pixelpass/NotoSans-OFL.txt"
+}
@@ -0,0 +1,52 @@
+# PeerSpeak + PixelPass — CachyOS/Arch test pack
+
+A single **split PKGBUILD** that builds the latest code from the public gitbutter
+repos and installs **both** programs at once:
+
+- `peerspeak` — decentralized P2P voice chat
+- `pixelpass` — P2P screen sharing (peerspeak launches it for the screen-share button)
+
+## Build & install (one command)
+
+```sh
+git clone https://gitbutter.xyz/mollusk/peerspeak.git
+cd peerspeak/packaging/test-pack
+makepkg -si
+```
+
+`makepkg -si` auto-installs every dependency via pacman before building —
+including the Rust toolchain itself (the `cargo` makedepend is provided by the
+`rust` package), `git`, `pkgconf`, pipewire + opus for peerspeak, and the
+gstreamer/VA-API stack for pixelpass. The only prerequisite is the `base-devel`
+group (which provides `makepkg`). If you already use `rustup`, that satisfies the
+`cargo` makedepend and the `rust` package won't be pulled in — no conflict.
+
+When it finishes you'll have `peerspeak` and `pixelpass` on your PATH at
+`/usr/bin`. To rebuild later with fresh upstream code, re-run `makepkg -si`; the
+git sources re-pull `main` and the version bumps automatically.
+
+> Skip the test step with `makepkg -si --nocheck` for a faster build.
+
+## Running the cross-internet test
+
+1. Launch `peerspeak` on both machines.
+2. One person **creates** a room and shares the room code/ticket with the other.
+3. The other **joins** with that code.
+4. iroh does NAT hole-punching automatically; if a direct path can't be made it
+   falls back to a public n0 relay — **no port forwarding required**.
+5. Allow the app through any local firewall if prompted (outbound UDP / QUIC;
+   nothing needs to be opened inbound for relay mode).
+
+### What we're smoke-testing
+- Two real humans, two networks, over the internet.
+- Mic capture + remote playback both directions, no crackle/dropouts.
+- Mute / deafen, push-to-talk.
+- Text chat in-room.
+- Avatars (presets + custom upload) show up on the other side.
+- Screen share: click the screen-share control → it launches `pixelpass`; the
+  viewer opens in `mpv` on the receiving side.
+- Notification chimes (join/leave/etc.).
+- Leave / rejoin cleanly.
+
+If anything misbehaves, grab the log path peerspeak prints on startup and the
+exact repro steps.
@@ -0,0 +1,108 @@
+# PeerSpeak — how to install and join a call (Windows)
+
+PeerSpeak is a little voice-chat app — like a private phone call over the
+internet, with no account, no signup, and no company in the middle. You install
+it once, then you and I connect directly to each other.
+
+---
+
+## 1. Install it
+
+1. Double-click **`peerspeak-0.3.0-setup.exe`** (the file I sent you).
+
+2. **Windows will probably show a blue "Windows protected your PC" warning.**
+   This is normal — it shows up for any app that isn't from a big company with a
+   paid certificate. It is **not** a virus warning.
+   - Click **More info**
+   - Then click **Run anyway**
+
+3. Windows will ask *"Do you want to allow this app to make changes?"* — click
+   **Yes**.
+
+4. The setup window opens. Just keep clicking **Next**. Two checkboxes you'll
+   see along the way:
+   - **"Allow PeerSpeak through Windows Firewall"** — leave this **checked**
+     (it lets the call connect without interruptions).
+   - **"Create a desktop shortcut"** — check it if you'd like an icon on your
+     desktop.
+
+5. Click **Install**, then **Finish**. PeerSpeak opens.
+
+That's it — it's installed. You can find it again any time from the **Start
+menu** (search "PeerSpeak").
+
+---
+
+## 2. Get on a call with me
+
+PeerSpeak connects two people using a **room ticket** — a long code that acts
+like a one-time phone number for a specific call.
+
+**The simple way (I host):**
+
+1. I'll create a room and send you a **ticket** (a long jumble of letters and
+   numbers).
+2. Copy the whole ticket I sent you.
+3. In PeerSpeak, paste it into the **"Join Room"** box near the bottom and press
+   **Join**.
+4. You're in — you should see both our names listed, and we can talk.
+
+**If you want to host instead:**
+
+1. Type a room name and click **Create New Room**.
+2. PeerSpeak gives you a **ticket** — click **Copy Ticket** and send it to me.
+3. I paste it on my end and join you.
+
+Either way works the same; it just depends on who makes the room.
+
+---
+
+## 3. While you're on a call
+
+- **Your microphone** is on by default. There's a **mute** button if you need
+  it.
+- The first time, Windows might ask for permission to use your **microphone** —
+  click **Yes / Allow**.
+- If you can't hear me or I can't hear you, open **Settings** (top right) and
+  check that the right **microphone** and **speakers/headphones** are selected.
+- To hang up, click **Leave Room**.
+
+---
+
+## 4. Chatting and sharing photos/files
+
+There's a **text chat** box at the bottom of the call window — type a message
+and press **Enter** to send it to everyone in the room.
+
+You can also **send a photo or a file**:
+
+1. Click the **attach button** (the small paperclip-style button) next to the
+   message box.
+2. Pick a photo or file from your computer.
+3. It sends to everyone in the room. **Photos show up right in the chat**;
+   other files appear as a small download chip with the file's name.
+
+To **save** a file someone sent you, click the **Save** (or **Download**)
+button next to it in the chat and choose where to put it.
+
+A couple of notes:
+- There's a size limit of about **25 MB** per file — bigger files are turned
+  away with a message.
+- Shared files only last for the **current call**. They aren't saved anywhere
+  automatically, so save anything you want to keep before you leave the room.
+
+---
+
+## Troubleshooting
+
+- **"I don't hear anything."** Open Settings and pick the correct microphone and
+  output device. Headphones are best — they prevent echo.
+- **"It won't connect."** Make sure you pasted the *entire* ticket (they're
+  long and easy to cut off). If it still won't connect, we may just need a fresh
+  ticket — they're meant to be used right away. Also make sure we're both on the
+  **same version** — if I've sent you an updated installer, install it (an old
+  version and a new one can't connect to each other).
+- **The blue warning again.** Same as install: **More info → Run anyway**. It's
+  the unsigned-app warning, not malware.
+
+Any trouble, just message me and we'll sort it out.
@@ -0,0 +1,84 @@
+# PeerSpeak — Windows installer
+
+This directory builds a Windows setup installer for PeerSpeak using
+[Inno Setup](https://jrsoftware.org/isinfo.php).
+
+PeerSpeak ships as a **single self-contained `peerspeak.exe`** — the GUI icon,
+notification chimes, and avatar presets are all embedded in the binary
+(`include_bytes!`), and the executable is statically linked against the GNU
+runtime, so there are no extra DLLs to bundle. The installer payload is just the
+`.exe` plus an `.ico` for the Start-menu / desktop shortcuts.
+
+## Version compatibility
+
+The installer version tracks the crate version in `Cargo.toml` (currently
+**0.3.0**) — keep `MyAppVersion` in `peerspeak.iss` in sync when it changes.
+
+Per `VERSIONING.md`, a **MINOR** bump in `0.x` is a **breaking wire change**:
+peers on different MINOR versions can't connect (they fail fast at the
+handshake rather than misbehaving). So when you ship a new Windows build after
+a MINOR bump, **everyone on the call must reinstall** — an old Windows build
+and a newer Linux/Windows peer won't talk. (0.3.0 was the chat file-sharing +
+per-peer noise-gate release; it cannot connect to a 0.2.x peer.)
+
+## Files
+
+| File | Tracked | Purpose |
+|------|---------|---------|
+| `peerspeak.iss` | yes | Inno Setup script |
+| `peerspeak.ico` | yes | multi-resolution app icon (from `assets/icons/*.png`) |
+| `README.md` | yes | this file |
+| `peerspeak.exe` | no (gitignored) | staged build artifact, copied from `target/x86_64-pc-windows-gnu/release/` |
+| `output/peerspeak-<ver>-setup.exe` | no (gitignored) | the compiled installer |
+
+## Build steps
+
+1. **Cross-compile the Windows binary** (from the repo root, inside the
+   `peerspeak-win` archlinux distrobox):
+
+   ```sh
+   RUSTC_BOOTSTRAP=1 ./win-cross-build.sh -Z build-std=std,panic_abort
+   ```
+
+   This needs the `rust-src` component and the `x86_64-pc-windows-gnu` target
+   installed in that toolchain. The result is a statically-linked,
+   GUI-subsystem `.exe` (no stray console window).
+
+2. **Stage the binary** next to the script:
+
+   ```sh
+   cp target/x86_64-pc-windows-gnu/release/peerspeak.exe packaging/windows/
+   ```
+
+3. **Regenerate the icon** if the source PNGs changed:
+
+   ```sh
+   magick assets/icons/peerspeak-16.png assets/icons/peerspeak-24.png \
+          assets/icons/peerspeak-32.png assets/icons/peerspeak-48.png \
+          assets/icons/peerspeak-64.png assets/icons/peerspeak-128.png \
+          assets/icons/peerspeak-256.png packaging/windows/peerspeak.ico
+   ```
+
+4. **Compile the installer** with Inno Setup. On Linux this runs under Wine:
+
+   ```sh
+   cd packaging/windows
+   wine ~/.wine/drive_c/InnoSetup6/ISCC.exe peerspeak.iss
+   ```
+
+   The installer lands at `output/peerspeak-<version>-setup.exe`.
+
+## What the installer does
+
+- Installs `peerspeak.exe` to `Program Files\PeerSpeak` (requires admin / one
+  UAC prompt).
+- Creates a Start-menu shortcut, with an optional desktop shortcut.
+- Optionally adds a Windows Firewall allow-rule for PeerSpeak (recommended —
+  iroh uses UDP hole-punching, so this avoids a mid-call firewall prompt). The
+  rule is removed on uninstall.
+- Provides a standard uninstaller.
+
+> **Note:** the installer and the binary are **not code-signed**, so Windows
+> SmartScreen will show an "unknown publisher" warning on first run. The user
+> clicks *More info → Run anyway*. Removing this warning requires a paid
+> code-signing certificate.
@@ -0,0 +1,63 @@
+; Inno Setup script for PeerSpeak (Windows installer).
+;
+; PeerSpeak is a single self-contained binary: the GUI icon, notification
+; chimes, and avatar presets are all embedded in the .exe (include_bytes!),
+; so the only payload here is peerspeak.exe plus an .ico for the shortcuts.
+;
+; Build (under Wine on Linux, or native Windows):
+;   wine "C:\Program Files (x86)\Inno Setup 6\ISCC.exe" peerspeak.iss
+; Output lands in .\output\peerspeak-<version>-setup.exe
+;
+; The peerspeak.exe is cross-compiled with win-cross-build.sh
+; (x86_64-pc-windows-gnu, statically linked -- no extra DLLs needed).
+
+#define MyAppName "PeerSpeak"
+#define MyAppVersion "0.3.0"
+#define MyAppPublisher "mollusk"
+#define MyAppExeName "peerspeak.exe"
+
+[Setup]
+; A stable AppId keeps upgrades/uninstall tracking consistent across versions.
+AppId={{2754D6C1-C8A4-4B13-9824-2D303439739D}
+AppName={#MyAppName}
+AppVersion={#MyAppVersion}
+AppVerName={#MyAppName} {#MyAppVersion}
+AppPublisher={#MyAppPublisher}
+DefaultDirName={autopf}\{#MyAppName}
+DefaultGroupName={#MyAppName}
+DisableProgramGroupPage=yes
+UninstallDisplayIcon={app}\{#MyAppExeName}
+SetupIconFile=peerspeak.ico
+Compression=lzma2/max
+SolidCompression=yes
+WizardStyle=modern
+OutputDir=output
+OutputBaseFilename=peerspeak-{#MyAppVersion}-setup
+; Program Files install + firewall rule both need elevation.
+PrivilegesRequired=admin
+ArchitecturesAllowed=x64compatible
+ArchitecturesInstallIn64BitMode=x64compatible
+
+[Languages]
+Name: "english"; MessagesFile: "compiler:Default.isl"
+
+[Tasks]
+Name: "desktopicon"; Description: "{cm:CreateDesktopIcon}"; GroupDescription: "{cm:AdditionalIcons}"; Flags: unchecked
+Name: "firewall"; Description: "Allow PeerSpeak through Windows Firewall (recommended for voice calls)"; GroupDescription: "Network:"
+
+[Files]
+Source: "peerspeak.exe"; DestDir: "{app}"; Flags: ignoreversion
+Source: "peerspeak.ico"; DestDir: "{app}"; Flags: ignoreversion
+
+[Icons]
+Name: "{group}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"; IconFilename: "{app}\peerspeak.ico"
+Name: "{group}\{cm:UninstallProgram,{#MyAppName}}"; Filename: "{uninstallexe}"
+Name: "{autodesktop}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"; IconFilename: "{app}\peerspeak.ico"; Tasks: desktopicon
+
+[Run]
+; iroh uses UDP hole-punching; pre-authorizing avoids a mid-call firewall prompt.
+Filename: "{sys}\netsh.exe"; Parameters: "advfirewall firewall add rule name=""PeerSpeak"" dir=in action=allow program=""{app}\{#MyAppExeName}"" enable=yes profile=any"; Flags: runhidden; Tasks: firewall
+Filename: "{app}\{#MyAppExeName}"; Description: "{cm:LaunchProgram,{#MyAppName}}"; Flags: nowait postinstall skipifsilent
+
+[UninstallRun]
+Filename: "{sys}\netsh.exe"; Parameters: "advfirewall firewall delete rule name=""PeerSpeak"""; Flags: runhidden; RunOnceId: "DelPeerSpeakFirewall"
@@ -2,7 +2,7 @@ use crate::core::{CoreController, messages::{CoreCommand, UiEvent}};
 use crate::network::PeerState;
 use crate::notify::{self, Sound};
 use crate::audio::eq::{EqSettings, EQ_GAIN_DB_MAX, EQ_GAIN_DB_MIN};
-use crate::audio::pw_cli::{AudioDevice, enumerate_audio_devices};
+use crate::audio::{AudioDevice, enumerate_audio_devices};
 use crate::config::{AppConfig, NetworkMode, RecordingMode, RoomLayout};
 use crate::hotkeys::{format_binding, HotkeyAction, HotkeyContext, KeyBinding};
 use crate::presence::PresenceMode;
@@ -114,6 +114,19 @@ struct ChatEntry {
    /// Sender's node id string, used to key their avatar colour (W4). `None` only
    /// for any future system-generated lines.
    from: Option<String>,
+    /// Optional file attachment descriptor. The bytes (if fetched) live in
+    /// `AppState.attachment_data` keyed by `attachment.id`; the entry only holds
+    /// the descriptor so history stays cheap.
+    attachment: Option<crate::files::ChatAttachment>,
+}
+
+/// Fetch state of a chat attachment's bytes (session-only).
+#[derive(Debug, Clone)]
+enum AttachmentState {
+    /// Bytes in hand (image decoded-valid, or a file ready to save).
+    Ready(Vec<u8>),
+    /// Fetch or decode failed; carries a short reason for the UI.
+    Failed(String),
 }

 /// Cap on retained chat history so a long call can't grow it without bound.
@@ -208,6 +221,7 @@ pub enum AppMessage {
    ClearHotkey(HotkeyAction),
    PeerVolumeChanged(EndpointId, f32),
    PeerPanChanged(EndpointId, f32),
+    PeerGateChanged(EndpointId, f32),
    PeerEqChanged(EndpointId, EqBand, f32),
    /// Toggle local mute of a peer (silence them just for us).
    TogglePeerMute(EndpointId),
@@ -263,6 +277,12 @@ pub enum AppMessage {
    ToggleRecording,
    /// Live edits to the chat input line.
    ChatInputChanged(String),
+    /// Open the native picker to attach a file to the chat.
+    PickAttachmentFile,
+    /// Result of the attach picker: (filename, bytes), or None if cancelled.
+    AttachmentFilePicked(Option<(String, Vec<u8>)>),
+    /// Save (downloading first if needed) a received attachment to disk.
+    SaveAttachment(crate::files::AttachmentId),
    /// Send the current chat input line (Enter or the Send button).
    ChatSubmit,
    /// Open a clicked chat link in the system browser (A13).
@@ -290,6 +310,15 @@ pub enum AppMessage {
    /// Result of the avatar file picker: the chosen file's raw bytes, or `None`
    /// if the user cancelled.
    AvatarFilePicked(Option<Vec<u8>>),
+    /// Open the native file picker to choose a custom UI background image (W16).
+    PickBackgroundFile,
+    /// Result of the background file picker: the chosen file's raw bytes, or
+    /// `None` if the user cancelled.
+    BackgroundFilePicked(Option<Vec<u8>>),
+    /// Clear the custom background, reverting to the theme background (W16).
+    RemoveBackground,
+    /// Set the background legibility scrim strength (0.0..=1.0) (W16).
+    SetBackgroundDim(f32),
    /// Toggle the Chat drawer open/closed (drawer layout).
    ToggleDrawerChat,
    /// Start/stop sharing our own screen (spawns/kills a pixelpass host).
@@ -335,8 +364,11 @@ pub struct AppState {
    selected_input: Option<AudioDevice>,
    selected_output: Option<AudioDevice>,
    config: AppConfig,
+    /// Decoded bytes of the custom background image (W16), cached so `view()`
+    /// doesn't read the file from disk on every redraw. Loaded on startup and
+    /// refreshed when the background is changed/removed. `None` = no custom bg.
+    background_image: Option<bytes::Bytes>,
    peers: HashMap<EndpointId, PeerState>,
-    peer_volumes: HashMap<EndpointId, f32>,
    audio_levels: HashMap<EndpointId, f32>,
    /// Peers we've locally muted (their audio isn't mixed into our output).
    locally_muted: HashSet<EndpointId>,
@@ -349,6 +381,15 @@ pub struct AppState {
    /// Room text-chat history (newest last) and the pending input line.
    chat_messages: Vec<ChatEntry>,
    chat_input: String,
+    /// Fetched/failed state for chat attachments, keyed by attachment id.
+    /// Session-only (cleared on leave); never persisted.
+    attachment_data: HashMap<crate::files::AttachmentId, AttachmentState>,
+    /// Cached iced image handles for ready image attachments, keyed by id, so we
+    /// don't re-upload to the GPU every redraw (the e917c53 avatar flicker fix).
+    image_handle_cache: HashMap<crate::files::AttachmentId, iced::widget::image::Handle>,
+    /// Attachment ids the user asked to save before the bytes arrived; when the
+    /// fetch completes a save dialog is opened for them.
+    pending_saves: std::collections::HashSet<crate::files::AttachmentId>,
    /// Last known window size, tracked so divider clamps stay valid on resize.
    /// (The divider positions themselves are persisted in `config`.)
    window_size: Size,
@@ -461,6 +502,16 @@ impl Default for AppState {
                let _ = controller.send(CoreCommand::SetPeerPan(id, *pan));
            }
        }
+        for (peer, volume) in &config.peer_volume {
+            if let Ok(id) = peer.parse::<EndpointId>() {
+                let _ = controller.send(CoreCommand::SetPeerVolume(id, *volume));
+            }
+        }
+        for (peer, threshold) in &config.peer_gate {
+            if let Ok(id) = peer.parse::<EndpointId>() {
+                let _ = controller.send(CoreCommand::SetPeerGate(id, *threshold));
+            }
+        }
        let pixelpass_available =
            crate::screenshare::is_available(config.pixelpass_path.as_deref());
        let all_devices = enumerate_audio_devices();
@@ -470,6 +521,7 @@ impl Default for AppState {
        let selected_input = input_devices.iter().find(|d| d.name == config.input_device).cloned();
        let selected_output = output_devices.iter().find(|d| d.name == config.output_device).cloned();

+        let background_image = load_background_bytes(&config);

        Self {
            // Pre-fill the nickname with the last one used (or "Peer" by default).
@@ -489,14 +541,17 @@ impl Default for AppState {
            selected_input,
            selected_output,
            config,
+            background_image,
            peers: HashMap::new(),
-            peer_volumes: HashMap::new(),
            audio_levels: HashMap::new(),
            locally_muted: HashSet::new(),
            call_started: None,
            recording: false,
            recording_started: None,
            chat_messages: Vec::new(),
+            attachment_data: HashMap::new(),
+            image_handle_cache: HashMap::new(),
+            pending_saves: std::collections::HashSet::new(),
            chat_input: String::new(),
            window_size: Size::new(ww, wh),
            layout_picker_open: false,
@@ -533,6 +588,15 @@ fn theme(state: &AppState) -> Theme {
    state.config.theme.base_theme()
 }

+/// Read the custom background PNG (W16) from disk into memory, if one is set and
+/// readable. Called once on startup and whenever the background changes, so the
+/// per-frame `view()` never touches the filesystem. A missing/unreadable file
+/// silently yields `None` (the UI falls back to the theme background).
+fn load_background_bytes(config: &AppConfig) -> Option<bytes::Bytes> {
+    let path = config.background.as_deref()?;
+    std::fs::read(path).ok().map(bytes::Bytes::from)
+}
+
 pub fn run_gui() -> iced::Result {
    // Restore the last window size (saved on close). Position is restored too,
    // but only on X11 — Wayland's xdg-shell gives clients no way to set their own
@@ -540,7 +604,7 @@ pub fn run_gui() -> iced::Result {
    let saved = AppConfig::load();
    let init_size = iced::Size::new(saved.window_width, saved.window_height);
    let init_position = initial_window_position(saved.window_x, saved.window_y, is_wayland());
-    iced::application(AppState::default, update, view)
+    iced::application(AppState::default, update, view_with_background)
        .title("PeerSpeak P2P Voice Chat")
        .theme(theme)
        .subscription(subscription)
@@ -553,11 +617,9 @@ pub fn run_gui() -> iced::Result {
            // the icon from the .desktop file matched by app_id instead).
            icon: window_icon(),
            // app_id must match the .desktop basename so Wayland compositors
-            // (e.g. KWin) attach our launcher icon to the window.
-            platform_specific: iced::window::settings::PlatformSpecific {
-                application_id: "peerspeak".to_string(),
-                ..Default::default()
-            },
+            // (e.g. KWin) attach our launcher icon to the window. The field is
+            // Linux-only in iced (X11/Wayland); see platform_specific_settings().
+            platform_specific: platform_specific_settings(),
            // We save the final size ourselves on CloseRequested, then exit.
            exit_on_close_request: false,
            ..Default::default()
@@ -565,6 +627,22 @@ pub fn run_gui() -> iced::Result {
        .run()
 }

+/// Window `PlatformSpecific` settings. `application_id` (used by X11/Wayland to
+/// match our `.desktop` launcher icon) only exists in iced on Linux, so it is
+/// set there and left at defaults on Windows.
+#[cfg(target_os = "linux")]
+fn platform_specific_settings() -> iced::window::settings::PlatformSpecific {
+    iced::window::settings::PlatformSpecific {
+        application_id: "peerspeak".to_string(),
+        ..Default::default()
+    }
+}
+
+#[cfg(not(target_os = "linux"))]
+fn platform_specific_settings() -> iced::window::settings::PlatformSpecific {
+    iced::window::settings::PlatformSpecific::default()
+}
+
 /// Build the window icon from an embedded 128×128 straight-RGBA blob rendered
 /// from `assets/icons/peerspeak.svg`. Using `from_rgba` (always available) keeps
 /// us off iced's heavy `image` feature — the blob is raw pixels, no decoder.
@@ -706,6 +784,34 @@ fn set_peer_pan_config(config: &mut AppConfig, id: EndpointId, pan: f32) -> f32
    pan
 }

+/// Store the per-peer listener volume, clamped to the slider range. Unity gain
+/// (`1.0`) is the implicit default, so an at-unity entry is removed rather than
+/// stored to keep the config tidy. Returns the clamped value.
+fn set_peer_volume_config(config: &mut AppConfig, id: EndpointId, volume: f32) -> f32 {
+    let volume = volume.clamp(0.0, 2.0);
+    let key = id.to_string();
+    if (volume - 1.0).abs() <= 0.001 {
+        config.peer_volume.remove(&key);
+    } else {
+        config.peer_volume.insert(key, volume);
+    }
+    volume
+}
+
+/// Store the per-peer listener noise-gate threshold, clamped to the slider
+/// range. `0.0` means the gate is off, so an at-zero entry is removed rather
+/// than stored. Returns the clamped value.
+fn set_peer_gate_config(config: &mut AppConfig, id: EndpointId, threshold: f32) -> f32 {
+    let threshold = threshold.clamp(0.0, METER_MAX);
+    let key = id.to_string();
+    if threshold <= 0.0 {
+        config.peer_gate.remove(&key);
+    } else {
+        config.peer_gate.insert(key, threshold);
+    }
+    threshold
+}
+
 fn peer_eq_settings(config: &AppConfig, id: &EndpointId) -> EqSettings {
    config
        .peer_eq
@@ -874,6 +980,10 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
                    state.ever_connected.remove(&id);
                    notify::play(Sound::PeerLeave, state.config.custom_sound_peer_leave.as_deref());
                }
+                // Core-only recovery phase: presentation for this state lands in
+                // the separate UI follow-up. In particular, do not play the
+                // terminal ReconnectFailed chime here.
+                UiEvent::PeerRecoveryStarted { .. } => {}
                UiEvent::PeerConnectionFailed { id } => {
                    state.peers.remove(&id);
                    state.audio_levels.remove(&id);
@@ -917,19 +1027,45 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
                    state.recording_started = None;
                    state.status_message = format!("Saved recording → {path}");
                }
-                UiEvent::ChatMessage { from, name, text } => {
+                UiEvent::ChatMessage { from, name, text, attachment } => {
                    // Incoming peer content is untrusted — sanitize name + text.
+                    // (The attachment filename was already sanitized in core.)
                    let text = sanitize_chat(&text);
-                    if !text.is_empty() {
+                    // Keep the message if it has visible text OR an attachment (an
+                    // image with no caption is still a real message).
+                    if !text.is_empty() || attachment.is_some() {
                        let name = sanitize_chat(&name);
                        push_chat(&mut state.chat_messages, ChatEntry {
                            name,
                            text,
                            mine: false,
                            from: Some(from),
+                            attachment,
                        });
                    }
                }
+                UiEvent::AttachmentReady { id, data } => {
+                    // Bytes arrived. For images we can cache the iced handle now
+                    // (built once, not per redraw). If the user was waiting to save
+                    // this file, the save dialog is opened from update() below by
+                    // checking pending_saves — done lazily so this arm stays simple.
+                    if crate::files::validate_image_bytes(&data).is_some() {
+                        state.image_handle_cache.insert(
+                            id,
+                            iced::widget::image::Handle::from_bytes(data.clone()),
+                        );
+                    }
+                    let needs_save = state.pending_saves.remove(&id);
+                    state.attachment_data.insert(id, AttachmentState::Ready(data));
+                    if needs_save {
+                        save_attachment_to_disk(state, id);
+                    }
+                }
+                UiEvent::AttachmentFailed { id, error } => {
+                    state.pending_saves.remove(&id);
+                    state.attachment_data.insert(id, AttachmentState::Failed(error.clone()));
+                    state.status_message = format!("Attachment failed: {error}");
+                }
                UiEvent::ScreenShareStarted => {
                    state.self_sharing = true;
                    state.status_message = "Sharing your screen".to_string();
@@ -996,13 +1132,17 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
            state.config.save();
        }
        AppMessage::PeerVolumeChanged(id, vol) => {
-            state.peer_volumes.insert(id, vol);
+            let vol = set_peer_volume_config(&mut state.config, id, vol);
            let _ = state.controller.send(CoreCommand::SetPeerVolume(id, vol));
        }
        AppMessage::PeerPanChanged(id, pan) => {
            let pan = set_peer_pan_config(&mut state.config, id, pan);
            let _ = state.controller.send(CoreCommand::SetPeerPan(id, pan));
        }
+        AppMessage::PeerGateChanged(id, threshold) => {
+            let threshold = set_peer_gate_config(&mut state.config, id, threshold);
+            let _ = state.controller.send(CoreCommand::SetPeerGate(id, threshold));
+        }
        AppMessage::PeerEqChanged(id, band, gain_db) => {
            let settings = set_peer_eq_config(&mut state.config, id, band, gain_db);
            let _ = state.controller.send(CoreCommand::SetPeerEq(id, settings));
@@ -1329,6 +1469,73 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
                }
            }
        }
+        AppMessage::PickBackgroundFile => {
+            // Native picker off the UI thread; result returns as BackgroundFilePicked.
+            return Task::perform(
+                async {
+                    let handle = rfd::AsyncFileDialog::new()
+                        .add_filter("Images", &["png", "jpg", "jpeg", "webp", "bmp"])
+                        .set_title("Choose a background image")
+                        .pick_file()
+                        .await;
+                    match handle {
+                        Some(h) => Some(h.read().await),
+                        None => None,
+                    }
+                },
+                AppMessage::BackgroundFilePicked,
+            );
+        }
+        AppMessage::BackgroundFilePicked(picked) => {
+            if let Some(bytes) = picked {
+                match crate::background::process_background(&bytes) {
+                    Ok(png) => match AppConfig::background_path() {
+                        Some(path) => {
+                            if let Some(dir) = path.parent() {
+                                let _ = std::fs::create_dir_all(dir);
+                            }
+                            match std::fs::write(&path, &png) {
+                                Ok(()) => {
+                                    state.config.background =
+                                        Some(path.to_string_lossy().into_owned());
+                                    state.config.save();
+                                    // Refresh the in-memory cache from the bytes we
+                                    // just wrote (avoids re-reading from disk).
+                                    state.background_image = Some(bytes::Bytes::from(png));
+                                    state.status_message = "Background updated.".to_string();
+                                }
+                                Err(e) => {
+                                    state.status_message =
+                                        format!("Couldn't save background: {e}");
+                                }
+                            }
+                        }
+                        None => {
+                            state.status_message =
+                                "Couldn't find a config directory to save the background."
+                                    .to_string();
+                        }
+                    },
+                    Err(e) => {
+                        state.status_message = e;
+                    }
+                }
+            }
+        }
+        AppMessage::RemoveBackground => {
+            // Best-effort delete of our stored copy; clear the config + cache.
+            if let Some(path) = AppConfig::background_path() {
+                let _ = std::fs::remove_file(path);
+            }
+            state.config.background = None;
+            state.config.save();
+            state.background_image = None;
+            state.status_message = "Background removed.".to_string();
+        }
+        AppMessage::SetBackgroundDim(dim) => {
+            state.config.background_dim = dim.clamp(0.0, 1.0);
+            state.config.save();
+        }
        AppMessage::ToggleDrawerChat => {
            state.drawer_chat_open = !state.drawer_chat_open;
        }
@@ -1341,21 +1548,119 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
                    text: text.clone(),
                    mine: true,
                    from: Some(state.self_id.clone()),
+                    attachment: None,
                });
                let _ = state.controller.send(CoreCommand::SendChat(text));
                state.chat_input.clear();
            }
        }
+        AppMessage::PickAttachmentFile => {
+            // Native picker off the UI thread; returns (filename, bytes).
+            return Task::perform(
+                async {
+                    let handle = rfd::AsyncFileDialog::new()
+                        .set_title("Attach a file to the chat")
+                        .pick_file()
+                        .await;
+                    match handle {
+                        Some(h) => Some((h.file_name(), h.read().await)),
+                        None => None,
+                    }
+                },
+                AppMessage::AttachmentFilePicked,
+            );
+        }
+        AppMessage::AttachmentFilePicked(picked) => {
+            if let Some((name, bytes)) = picked {
+                let size = bytes.len() as u64;
+                if !crate::files::size_within_cap(size) {
+                    state.status_message = format!(
+                        "File too large — max {}.",
+                        crate::files::human_size(crate::files::MAX_ATTACHMENT_BYTES)
+                    );
+                    return Task::none();
+                }
+                let kind = crate::files::classify(&bytes);
+                // Random 32-byte handle for this attachment.
+                let id: crate::files::AttachmentId = rand::random();
+                let att = crate::files::ChatAttachment {
+                    name: crate::files::sanitize_filename(&name),
+                    size,
+                    kind,
+                    id,
+                };
+                // Keep our own bytes locally so we see our own attachment inline
+                // immediately (others fetch it off the file plane).
+                if kind == crate::files::AttachmentKind::Image
+                    && crate::files::validate_image_bytes(&bytes).is_some()
+                {
+                    state
+                        .image_handle_cache
+                        .insert(id, iced::widget::image::Handle::from_bytes(bytes.clone()));
+                }
+                state
+                    .attachment_data
+                    .insert(id, AttachmentState::Ready(bytes.clone()));
+                push_chat(
+                    &mut state.chat_messages,
+                    ChatEntry {
+                        name: format!("{} (You)", state.name),
+                        text: String::new(),
+                        mine: true,
+                        from: Some(state.self_id.clone()),
+                        attachment: Some(att.clone()),
+                    },
+                );
+                let _ = state.controller.send(CoreCommand::SendChatFile {
+                    text: String::new(),
+                    attachment: att,
+                    data: bytes,
+                });
+            }
+        }
+        AppMessage::SaveAttachment(id) => {
+            // If we already have the bytes, save now; otherwise fetch from the
+            // sender and save when AttachmentReady arrives (pending_saves).
+            if matches!(state.attachment_data.get(&id), Some(AttachmentState::Ready(_))) {
+                save_attachment_to_disk(state, id);
+            } else if let Some((from, att)) = find_attachment_source(state, id) {
+                if let Ok(eid) = from.parse::<EndpointId>() {
+                    state.pending_saves.insert(id);
+                    state.status_message = format!("Downloading {}…", att.name);
+                    let _ = state
+                        .controller
+                        .send(CoreCommand::FetchAttachment { from: eid, attachment: att });
+                } else {
+                    state.status_message = "Can't download: unknown sender.".to_string();
+                }
+            }
+        }
        AppMessage::OpenUrl(url) => {
            // Defence in depth: only ever hand http(s) URLs to the opener. The
            // link span's href came from `linkify`, which only emits http/https,
            // but re-check here so this can't be widened into launching arbitrary
-            // schemes/args. `xdg-open` receives the URL as a single argv entry
-            // (no shell), so there's no injection surface.
-            if (url.starts_with("http://") || url.starts_with("https://"))
-                && let Err(e) = std::process::Command::new("xdg-open").arg(&url).spawn()
-            {
-                crate::log_msg(&format!("Failed to open URL {url:?}: {e}"));
+            // schemes/args. Each opener receives the URL as a single argv entry
+            // (no shell), so there's no injection surface:
+            //   - Unix: `xdg-open <url>`.
+            //   - Windows: `rundll32 url.dll,FileProtocolHandler <url>` — opens the
+            //     default browser without going through `cmd`/`start`, which would
+            //     otherwise re-parse `&` in query strings.
+            if url.starts_with("http://") || url.starts_with("https://") {
+                let spawned = {
+                    #[cfg(unix)]
+                    {
+                        std::process::Command::new("xdg-open").arg(&url).spawn()
+                    }
+                    #[cfg(windows)]
+                    {
+                        std::process::Command::new("rundll32")
+                            .args(["url.dll,FileProtocolHandler", &url])
+                            .spawn()
+                    }
+                };
+                if let Err(e) = spawned {
+                    crate::log_msg(&format!("Failed to open URL {url:?}: {e}"));
+                }
            }
        }
        AppMessage::ToggleMicTest(enabled) => {
@@ -1563,6 +1868,54 @@ fn push_chat(messages: &mut Vec<ChatEntry>, entry: ChatEntry) {
    }
 }

+/// Find the sender id + descriptor for a received attachment by its id, so a
+/// fetch can be addressed. Returns `None` for our own attachments or an unknown
+/// id.
+fn find_attachment_source(
+    state: &AppState,
+    id: crate::files::AttachmentId,
+) -> Option<(String, crate::files::ChatAttachment)> {
+    state.chat_messages.iter().find_map(|m| {
+        let att = m.attachment.as_ref()?;
+        if att.id == id && !m.mine {
+            Some((m.from.clone()?, att.clone()))
+        } else {
+            None
+        }
+    })
+}
+
+/// Write a ready attachment's bytes to a user-chosen location via a native save
+/// dialog. The default filename comes from the (already-sanitized) descriptor.
+/// No-op if the bytes aren't ready. Sync dialog: the brief block is acceptable
+/// for a deliberate save action.
+fn save_attachment_to_disk(state: &mut AppState, id: crate::files::AttachmentId) {
+    let Some(AttachmentState::Ready(data)) = state.attachment_data.get(&id) else {
+        return;
+    };
+    let data = data.clone();
+    let default_name = state
+        .chat_messages
+        .iter()
+        .find_map(|m| {
+            m.attachment
+                .as_ref()
+                .filter(|a| a.id == id)
+                .map(|a| a.name.clone())
+        })
+        .unwrap_or_else(|| "download".to_string());
+    if let Some(path) = rfd::FileDialog::new()
+        .set_file_name(default_name)
+        .set_title("Save attachment")
+        .save_file()
+    {
+        match std::fs::write(&path, &data) {
+            Ok(()) => state.status_message = format!("Saved {}", path.display()),
+            Err(e) => state.status_message = format!("Save failed: {e}"),
+        }
+    }
+}
+
 fn horizontal_space() -> iced::widget::Space {
    iced::widget::Space::new().width(iced::Length::Fill)
 }
@@ -1984,6 +2337,40 @@ fn friends_panel(state: &AppState) -> Element<'_, AppMessage> {
    .into()
 }

+/// Wrap the main [`view`] with the custom background layer (W16). When a
+/// background image is set, render `stack![ image(Cover), scrim, ui ]` so the
+/// photo sits behind the whole UI with a legibility scrim (the theme base colour
+/// at `background_dim` alpha) between them; otherwise return the UI untouched. The
+/// three screen roots go transparent (`root_bg` in `view`) so the image shows
+/// through the gaps between panels. This is the registered top-level view.
+fn view_with_background(state: &AppState) -> Element<'_, AppMessage> {
+    let content = view(state);
+    let Some(bytes) = state.background_image.clone() else {
+        return content;
+    };
+    let pal = state.config.theme.palette();
+    let dim = state.config.background_dim;
+    let image_layer = iced::widget::image(cached_image_handle(bytes))
+        .content_fit(iced::ContentFit::Cover)
+        .width(iced::Length::Fill)
+        .height(iced::Length::Fill);
+    let scrim = container(
+        iced::widget::Space::new()
+            .width(iced::Length::Fill)
+            .height(iced::Length::Fill),
+    )
+    .width(iced::Length::Fill)
+    .height(iced::Length::Fill)
+    .style(move |_: &Theme| container::Style {
+        background: Some(Background::Color(crate::background::scrim_color(pal.base, dim))),
+        ..Default::default()
+    });
+    iced::widget::stack![image_layer, scrim, content]
+        .width(iced::Length::Fill)
+        .height(iced::Length::Fill)
+        .into()
+}
+
 fn view(state: &AppState) -> Element<'_, AppMessage> {
    // Theme colours — sourced from the active palette (see `src/theme.rs`), so
    // all styling below re-themes when the user picks a different theme.
@@ -2002,6 +2389,16 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
    let color_green = pal.green;
    let color_yellow = pal.yellow;

+    // The window backdrop fill for the three screen roots. When a custom
+    // background image is set (W16), the root goes transparent so the image +
+    // scrim layered behind by `view_with_background` shows through the gaps
+    // between panels; otherwise it's the usual opaque `crust`.
+    let root_bg = if state.background_image.is_some() {
+        Color::TRANSPARENT
+    } else {
+        color_crust
+    };
+
    // Style Helpers
    let c_style = move |bg: Color, b_color: Color, radius: f32| {
        move |_theme: &Theme| container::Style {
@@ -2263,6 +2660,35 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
        .spacing(10)
        .width(iced::Length::Fill);

+        let remove_background: Element<'_, AppMessage> = if state.config.background.is_some() {
+            button(text("Remove background").size(13))
+                .on_press(AppMessage::RemoveBackground)
+                .style(b_style(color_surface, color_blue, color_text, 6.0))
+                .padding(8)
+                .into()
+        } else {
+            iced::widget::Space::new().width(0.0).height(0.0).into()
+        };
+        let background_section = column![
+            row![
+                button(text("Choose image…").size(13))
+                    .on_press(AppMessage::PickBackgroundFile)
+                    .style(b_style(color_surface, color_blue, color_text, 6.0))
+                    .padding(8),
+                remove_background,
+            ].spacing(8),
+            text(format!("Background dimming: {:.0}%", state.config.background_dim * 100.0))
+                .size(11)
+                .color(color_subtext),
+            slider(0.0..=1.0, state.config.background_dim, AppMessage::SetBackgroundDim)
+                .step(0.05),
+            text("Set a picture from your computer as the app background. Auto-resized; a dimming overlay keeps text readable. Applies live.")
+                .size(11)
+                .color(color_subtext),
+        ]
+        .spacing(10)
+        .width(iced::Length::Fill);
+
        // Inline avatar chooser (W4): the monogram fallback plus the bundled
        // presets, each a clickable tile. Same SelectAvatar message, applied live
        // + persisted (and re-announced to the room).
@@ -2541,10 +2967,28 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
                    mic_meter,
                    text("Drag the yellow handle to set the gate. While talking, place it just above your quiet-room level so silence is muted but your voice passes through.").size(11).color(color_subtext),
                    vertical_space(4.0),
-                    checkbox(state.config.echo_cancellation_enabled)
-                        .label("Echo cancellation")
-                        .on_toggle(AppMessage::ToggleEchoCancellation),
-                    text("Cancels speaker echo + suppresses noise (PipeWire). Takes effect on your next room join.").size(11).color(color_subtext),
+                    {
+                        let control: Element<'_, AppMessage> = {
+                            #[cfg(target_os = "linux")]
+                            {
+                                column![
+                                    checkbox(state.config.echo_cancellation_enabled)
+                                        .label("Echo cancellation")
+                                        .on_toggle(AppMessage::ToggleEchoCancellation),
+                                    text("Cancels speaker echo + suppresses noise (PipeWire). Takes effect on your next room join.").size(11).color(color_subtext),
+                                ].spacing(8).into()
+                            }
+                            #[cfg(not(target_os = "linux"))]
+                            {
+                                column![
+                                    checkbox(false)
+                                        .label("Echo cancellation"),
+                                    text("Echo cancellation is not available on Windows yet.").size(11).color(color_subtext),
+                                ].spacing(8).into()
+                            }
+                        };
+                        control
+                    },
                ].spacing(8).width(iced::Length::Fill),
            ]
            .spacing(10)
@@ -2593,6 +3037,9 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
                vertical_space(section_gap),
                section_header("Theme"),
                theme_section,
+                vertical_space(section_gap),
+                section_header("Background"),
+                background_section,
            ]
            .spacing(10)
            .width(iced::Length::Fill)
@@ -2778,7 +3225,7 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
            .height(iced::Length::Fill)
            .padding(24)
            .center_x(iced::Length::Fill)
-            .style(c_style(color_crust, Color::TRANSPARENT, 0.0));
+            .style(c_style(root_bg, Color::TRANSPARENT, 0.0));

        return with_regenerate_confirm(settings_screen.into(), state);
    }
@@ -2837,7 +3284,7 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
        )
            .width(iced::Length::Fill)
            .height(iced::Length::Fill)
-            .style(c_style(color_crust, Color::TRANSPARENT, 0.0));
+            .style(c_style(root_bg, Color::TRANSPARENT, 0.0));

        with_hotkey_info(with_layout_picker(home.into(), state), state)
    } else {
@@ -3129,11 +3576,18 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
            ].spacing(8);

            // Peer volume slider
-            let current_vol = state.peer_volumes.get(peer_id).copied().unwrap_or(1.0);
+            let current_vol = state
+                .config
+                .peer_volume
+                .get(&peer_id.to_string())
+                .copied()
+                .unwrap_or(1.0);
            card_content = card_content.push(
                row![
                    text("Vol:").size(12).color(color_subtext),
                    slider(0.0..=2.0, current_vol, move |v| AppMessage::PeerVolumeChanged(peer_id_clone, v))
+                        .step(0.01)
+                        .on_release(AppMessage::PersistConfig)
                ].spacing(8).align_y(iced::alignment::Vertical::Center)
            );

@@ -3152,6 +3606,28 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
                .align_y(iced::alignment::Vertical::Center),
            );

+            // Peer noise gate: suppress this peer's background noise on our end.
+            // Threshold is normalized RMS on the same 0..METER_MAX scale as the
+            // mic gate; 0 = off.
+            let current_gate = state.config.peer_gate.get(&peer_key).copied().unwrap_or(0.0);
+            let gate_label = if current_gate <= 0.0 {
+                "Off".to_string()
+            } else {
+                format!("{:.0}%", (current_gate / METER_MAX * 100.0).clamp(0.0, 100.0))
+            };
+            card_content = card_content.push(
+                row![
+                    text("Gate:").size(12).color(color_subtext),
+                    container(text(gate_label).size(11).color(color_subtext))
+                        .width(iced::Length::Fixed(58.0)),
+                    slider(0.0..=METER_MAX, current_gate, move |v| AppMessage::PeerGateChanged(peer_id_clone, v))
+                        .step(0.001)
+                        .on_release(AppMessage::PersistConfig),
+                ]
+                .spacing(8)
+                .align_y(iced::alignment::Vertical::Center),
+            );
+
            let eq = peer_eq_settings(&state.config, peer_id);
            let eq_row = |label: &'static str, band: EqBand, value: f32| -> Element<'_, AppMessage> {
                row![
@@ -3247,26 +3723,40 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
                column![]
            },
            vertical_space(20.0),
-            // Echo cancellation — same flag + message as the Settings checkbox, so
-            // toggling here and there stay in sync automatically (single source of
-            // truth: config.echo_cancellation_enabled). Tooltip is explicit that it
-            // applies on the NEXT join (the PipeWire-module AEC is wired at join
-            // time, not hot-swappable mid-call).
-            tooltip(
-                checkbox(state.config.echo_cancellation_enabled)
-                    .label("Echo cancellation")
-                    .on_toggle(AppMessage::ToggleEchoCancellation),
-                container(
-                    text("Cancels speaker echo + suppresses noise. Applies on your next room join.")
-                        .size(11)
-                        .color(color_text),
-                )
-                .padding(8)
-                .max_width(260.0)
-                .style(c_style(color_crust, color_surface, 6.0)),
-                iced::widget::tooltip::Position::Top,
-            )
-            .gap(8),
+            {
+                // Echo cancellation is wired at join time on Linux; other
+                // targets show an inert status row instead of a dead toggle.
+                let control: Element<'_, AppMessage> = {
+                    #[cfg(target_os = "linux")]
+                    {
+                        tooltip(
+                            checkbox(state.config.echo_cancellation_enabled)
+                                .label("Echo cancellation")
+                                .on_toggle(AppMessage::ToggleEchoCancellation),
+                            container(
+                                text("Cancels speaker echo + suppresses noise. Applies on your next room join.")
+                                    .size(11)
+                                    .color(color_text),
+                            )
+                            .padding(8)
+                            .max_width(260.0)
+                            .style(c_style(color_crust, color_surface, 6.0)),
+                            iced::widget::tooltip::Position::Top,
+                        )
+                        .gap(8)
+                        .into()
+                    }
+                    #[cfg(not(target_os = "linux"))]
+                    {
+                        column![
+                            checkbox(false)
+                                .label("Echo cancellation"),
+                            text("Not available on Windows yet.").size(11).color(color_subtext),
+                        ].spacing(4).into()
+                    }
+                };
+                control
+            },
            vertical_space(20.0),
            {
                let (rec_kind, rec_label, rec_bg, rec_hover, rec_fg) = if state.recording {
@@ -3390,6 +3880,59 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
                    .spacing(8)
                    .align_y(iced::alignment::Vertical::Top),
                );
+                // Attachment row (indented under the message), if any.
+                if let Some(att) = &m.attachment {
+                    let data = state.attachment_data.get(&att.id);
+                    let elem: Element<'_, AppMessage> =
+                        if let Some(AttachmentState::Failed(e)) = data {
+                            text(format!("⚠ {} — {e}", att.name))
+                                .size(12)
+                                .color(color_red)
+                                .into()
+                        } else if att.kind == crate::files::AttachmentKind::Image {
+                            match state.image_handle_cache.get(&att.id) {
+                                Some(handle) => iced::widget::image(handle.clone())
+                                    .width(iced::Length::Fixed(260.0))
+                                    .into(),
+                                None => text(format!("🖼 {} — loading…", att.name))
+                                    .size(12)
+                                    .color(color_subtext)
+                                    .into(),
+                            }
+                        } else {
+                            let ready =
+                                matches!(data, Some(AttachmentState::Ready(_)));
+                            let btn_label = if ready { "Save" } else { "Download" };
+                            row![
+                                text(format!(
+                                    "📎 {} ({})",
+                                    att.name,
+                                    crate::files::human_size(att.size)
+                                ))
+                                .size(12)
+                                .color(color_text),
+                                button(text(btn_label).size(12))
+                                    .on_press(AppMessage::SaveAttachment(att.id))
+                                    .style(b_style(
+                                        color_blue,
+                                        color_lavender,
+                                        color_crust,
+                                        6.0,
+                                    ))
+                                    .padding(6),
+                            ]
+                            .spacing(8)
+                            .align_y(iced::alignment::Vertical::Center)
+                            .into()
+                        };
+                    chat_col = chat_col.push(
+                        row![
+                            iced::widget::Space::new().width(iced::Length::Fixed(30.0)),
+                            elem
+                        ]
+                        .spacing(0),
+                    );
+                }
            }
        }
        let chat_scroll = scrollable(chat_col)
@@ -3397,6 +3940,10 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
            .height(iced::Length::Fill)
            .anchor_bottom();
        let chat_input_row = row![
+            button(text("📎").size(15))
+                .on_press(AppMessage::PickAttachmentFile)
+                .style(b_style(color_surface, color_overlay, color_text, 6.0))
+                .padding(8),
            text_input("Message the room…", &state.chat_input)
                .on_input(AppMessage::ChatInputChanged)
                .on_submit(AppMessage::ChatSubmit)
@@ -3524,7 +4071,7 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
        .padding(15)
        .width(iced::Length::Fill)
        .height(iced::Length::Fill)
-        .style(c_style(color_crust, Color::TRANSPARENT, 0.0));
+        .style(c_style(root_bg, Color::TRANSPARENT, 0.0));

        with_hotkey_info(
            with_pixelpass_help(with_layout_picker(room.into(), state), state),
@@ -4667,8 +5214,48 @@ impl Program<AppMessage> for Icon {
 mod tests {
    use super::{
        format_duration, initial_window_position, reconnect_attempt_chime, reconnected_chime,
-        GateMeter, METER_MAX,
+        set_peer_gate_config, set_peer_volume_config, AppConfig, GateMeter, METER_MAX,
    };
+    use iroh::SecretKey;
+
+    #[test]
+    fn peer_gate_persists_when_on_and_clears_when_off() {
+        let mut config = AppConfig::default();
+        let id = SecretKey::generate().public();
+
+        // A positive threshold is stored, clamped to the slider's METER_MAX ceiling.
+        let stored = set_peer_gate_config(&mut config, id, 0.05);
+        assert_eq!(stored, 0.05);
+        assert_eq!(config.peer_gate.get(&id.to_string()).copied(), Some(0.05));
+        assert_eq!(set_peer_gate_config(&mut config, id, 99.0), METER_MAX);
+
+        // Zero (or negative) means "gate off" — the entry is removed so the
+        // config doesn't carry a disabled gate.
+        let stored = set_peer_gate_config(&mut config, id, 0.0);
+        assert_eq!(stored, 0.0);
+        assert!(!config.peer_gate.contains_key(&id.to_string()));
+    }
+
+    #[test]
+    fn peer_volume_persists_non_unity_and_clears_at_unity() {
+        let mut config = AppConfig::default();
+        let id = SecretKey::generate().public();
+
+        // A non-unity value is clamped into range and stored.
+        let stored = set_peer_volume_config(&mut config, id, 1.5);
+        assert_eq!(stored, 1.5);
+        assert_eq!(config.peer_volume.get(&id.to_string()).copied(), Some(1.5));
+
+        // Out-of-range values clamp to the slider bounds.
+        assert_eq!(set_peer_volume_config(&mut config, id, 5.0), 2.0);
+        assert_eq!(set_peer_volume_config(&mut config, id, -1.0), 0.0);
+
+        // Returning to unity removes the entry (unity is the implicit default),
+        // so the config doesn't accumulate no-op entries.
+        let stored = set_peer_volume_config(&mut config, id, 1.0);
+        assert_eq!(stored, 1.0);
+        assert!(!config.peer_volume.contains_key(&id.to_string()));
+    }

    #[test]
    fn x11_restores_saved_window_position() {
@@ -4943,6 +5530,7 @@ mod tests {
            text: "Hello".to_string(),
            mine: true,
            from: None,
+            attachment: None,
        };
        push_chat(&mut messages, entry);
        assert_eq!(messages.len(), 1);
@@ -4963,6 +5551,7 @@ mod tests {
                    text: format!("Msg{}", i),
                    mine: i % 2 == 0,
                    from: None,
+                    attachment: None,
                },
            );
        }
@@ -4986,6 +5575,7 @@ mod tests {
                    text: format!("Msg{}", i),
                    mine: i % 2 == 0,
                    from: None,
+                    attachment: None,
                },
            );
        }
@@ -56,12 +56,60 @@ pub trait AudioBackend: Send + Sync {
    fn stop(&self) -> Result<(), AudioError>;
 }

-pub mod echo_cancel;
 pub mod eq;
 pub mod gate;
 pub mod limiter;
 pub mod multitrack;
 pub mod pan;
+// Linear resamplers used by the Windows/cpal backend (W4). Platform-neutral and
+// pure, so it builds (and its tests run) everywhere even though only the cpal
+// backend wires it in.
+pub mod resample;
+#[cfg(target_os = "linux")]
+pub mod echo_cancel;
+#[cfg(target_os = "linux")]
 pub mod pipewire_impl;
+#[cfg(windows)]
+pub mod cpal_impl;
+#[cfg(target_os = "linux")]
 pub mod pw_cli;
 pub mod recorder;
+
+/// A selectable audio device for the input/output pickers. `name` is the stable
+/// identifier the backend uses to request the device (`target_node`);
+/// `description` is the human-facing label shown in the UI. The two may be equal
+/// (cpal/WASAPI) or differ (PipeWire node name vs. description).
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct AudioDevice {
+    pub name: String,
+    pub description: String,
+    pub is_input: bool,
+}
+
+impl std::fmt::Display for AudioDevice {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.description)
+    }
+}
+
+// Enumerate audio input/output devices for the pickers (sorted by description),
+// returning the same `AudioDevice` shape regardless of platform: PipeWire
+// (`pw-cli`) on Linux, cpal/WASAPI on Windows.
+#[cfg(target_os = "linux")]
+pub use pw_cli::enumerate_audio_devices;
+#[cfg(windows)]
+pub use cpal_impl::enumerate_audio_devices;
+
+/// The audio backend implementation for the current platform.
+///
+/// The whole app constructs and threads this alias (via
+/// `PlatformAudioBackend::new()`) rather than any concrete backend type, so
+/// platform selection lives entirely here. Both implementations satisfy the
+/// [`AudioBackend`] trait, which is the only interface the core talks to.
+///
+/// - Linux → PipeWire ([`pipewire_impl::PipeWireBackend`]).
+/// - Windows → cpal/WASAPI ([`cpal_impl::CpalBackend`]).
+#[cfg(target_os = "linux")]
+pub type PlatformAudioBackend = pipewire_impl::PipeWireBackend;
+#[cfg(windows)]
+pub type PlatformAudioBackend = cpal_impl::CpalBackend;
@@ -1,18 +1,6 @@
+use super::AudioDevice;
 use std::process::Command;

-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct AudioDevice {
-    pub name: String,
-    pub description: String,
-    pub is_input: bool,
-}
-
-impl std::fmt::Display for AudioDevice {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.description)
-    }
-}
-
 pub fn enumerate_audio_devices() -> Vec<AudioDevice> {
    let output = Command::new("pw-cli")
        .arg("list-objects")
@@ -0,0 +1,307 @@
+//! Dep-free linear-interpolation resamplers for the Windows/cpal backend (W4).
+//!
+//! The pipeline runs internally at 48 kHz (Opus + the 20 ms frame), but a WASAPI
+//! endpoint may run at a different rate (commonly 44.1 kHz) and/or a non-stereo
+//! channel layout. These convert at the device boundary so such a device plays and
+//! captures instead of hard-erroring (the W4 limitation in the Windows port).
+//!
+//! ## Where each is used
+//! - [`PushResampler`] (single channel) converts **capture** from the device rate
+//!   to 48 kHz on the capture drain thread — off the RT callback.
+//! - [`StereoPullResampler`] converts **playback** from the internal 48 kHz stereo
+//!   bus to the device rate inside the output RT callback, pulling internal frames
+//!   from the ring on demand. It allocates nothing in `next`, so it is RT-safe.
+//!
+//! ## Quality
+//! This is plain linear interpolation with no anti-aliasing filter: correct,
+//! allocation-free, and adequate for speech, but it adds some aliasing when
+//! downsampling. The seam is intentionally tiny so a higher-quality polyphase/FIR
+//! resampler (e.g. the `rubato` crate, pending a supply-chain decision) can later
+//! replace the internals without touching the cpal backend. The matching-rate /
+//! matching-layout path in the backend bypasses these entirely and stays bit-exact.
+
+/// Linear interpolation between `a` and `b` at fractional position `frac` in `[0, 1)`.
+#[inline]
+fn lerp(a: f32, b: f32, frac: f32) -> f32 {
+    a + (b - a) * frac
+}
+
+/// Stateful single-channel **push** resampler: feed input samples at `in_rate`,
+/// receive output samples at `out_rate` through an `emit` callback. It carries the
+/// fractional read position and the previous input sample across calls, so feeding
+/// the stream block-by-block joins seamlessly. Neither [`push`](Self::push) nor
+/// [`process`](Self::process) allocates.
+pub struct PushResampler {
+    /// Input samples consumed per output sample (`in_rate / out_rate`).
+    step: f64,
+    /// Position of the next output sample, in input-sample units, measured from the
+    /// index of `prev` (the most recent input). Always advanced to stay `< 1.0`
+    /// after each input is consumed.
+    next: f64,
+    /// The previous input sample (left edge of the current interpolation segment).
+    prev: f32,
+    /// Whether any input has been seen yet (anchors the first output at input[0]).
+    started: bool,
+}
+
+impl PushResampler {
+    /// Build a resampler from `in_rate` to `out_rate` (both in Hz). Rates are
+    /// clamped to `>= 1` so `step` is always finite and non-zero: a zero `step`
+    /// would make [`push`](Self::push)'s `while self.next < 1.0` loop forever. The
+    /// cpal backend's `resolve()` also rejects such rates up front, so this is
+    /// belt-and-suspenders against a future caller (review W7).
+    pub fn new(in_rate: u32, out_rate: u32) -> Self {
+        Self {
+            step: in_rate.max(1) as f64 / out_rate.max(1) as f64,
+            next: 0.0,
+            prev: 0.0,
+            started: false,
+        }
+    }
+
+    /// Feed one input sample; `emit` is called for each output sample produced
+    /// (zero or more, depending on the rate ratio).
+    pub fn push(&mut self, cur: f32, mut emit: impl FnMut(f32)) {
+        if !self.started {
+            // First sample: just establish the left edge. Linear interpolation
+            // needs the next input as the right edge, so the first output is
+            // produced on the next push. This gives exact alignment
+            // (`output[k] == input[k]` at equal rates) with one input-sample of
+            // latency — negligible (~20 µs at 48 kHz).
+            self.started = true;
+            self.prev = cur;
+            self.next = 0.0;
+            return;
+        }
+        // `prev` sits at position 0 of this segment and `cur` at position 1; emit
+        // every output whose position falls in [0, 1).
+        while self.next < 1.0 {
+            emit(lerp(self.prev, cur, self.next as f32));
+            self.next += self.step;
+        }
+        self.next -= 1.0;
+        self.prev = cur;
+    }
+
+    /// Convenience for tests / batch callers: push a whole slice.
+    pub fn process(&mut self, input: &[f32], mut emit: impl FnMut(f32)) {
+        for &s in input {
+            self.push(s, &mut emit);
+        }
+    }
+}
+
+/// Stateful stereo **pull** resampler: produce output frames at `out_rate` by
+/// pulling input frames at `in_rate` from a closure on demand. Call
+/// [`next`](Self::next) once per output frame; it pulls as many input frames as the
+/// ratio requires and returns the interpolated `(left, right)`, or `None` when the
+/// puller runs dry (an underrun). Allocates nothing, so it is safe in an RT output
+/// callback.
+pub struct StereoPullResampler {
+    /// Input frames consumed per output frame (`in_rate / out_rate`).
+    step: f64,
+    /// Position of the next output frame within `[prev, cur)`, in `[0, 1)`.
+    frac: f64,
+    /// Left edge of the current interpolation segment.
+    prev: (f32, f32),
+    /// Right edge of the current interpolation segment.
+    cur: (f32, f32),
+    /// Whether `prev`/`cur` have been primed from the puller yet.
+    primed: bool,
+}
+
+impl StereoPullResampler {
+    /// Build a resampler from `in_rate` to `out_rate` (both in Hz). Rates are
+    /// clamped to `>= 1` so `step` is finite and non-zero — otherwise
+    /// [`next`](Self::next)'s `while self.frac >= 1.0` could spin (review W7).
+    pub fn new(in_rate: u32, out_rate: u32) -> Self {
+        Self {
+            step: in_rate.max(1) as f64 / out_rate.max(1) as f64,
+            frac: 0.0,
+            prev: (0.0, 0.0),
+            cur: (0.0, 0.0),
+            primed: false,
+        }
+    }
+
+    /// Produce the next output frame, pulling input frames via `pull` as needed.
+    /// Returns `None` if `pull` returns `None` before the frame can be formed
+    /// (underrun); the caller should substitute silence for that frame.
+    pub fn next(&mut self, mut pull: impl FnMut() -> Option<(f32, f32)>) -> Option<(f32, f32)> {
+        if !self.primed {
+            // Prime both edges from two pulls so the first output frame aligns
+            // exactly with the first input frame (`out[0] == in[0]` at equal
+            // rates). Needs two frames available to start, which the prefilled
+            // playback ring always has.
+            self.prev = pull()?;
+            self.cur = pull()?;
+            self.primed = true;
+            self.frac = 0.0;
+        }
+        // Advance the segment until the read position lands inside [prev, cur).
+        while self.frac >= 1.0 {
+            self.prev = self.cur;
+            self.cur = pull()?;
+            self.frac -= 1.0;
+        }
+        let f = self.frac as f32;
+        let out = (lerp(self.prev.0, self.cur.0, f), lerp(self.prev.1, self.cur.1, f));
+        self.frac += self.step;
+        Some(out)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// Equal rates align exactly: `output[k] == input[k]`. The final input lands on
+    /// the next push (one-sample streaming latency), so we get `n - 1` outputs.
+    #[test]
+    fn push_identity_when_rates_match() {
+        let mut r = PushResampler::new(48_000, 48_000);
+        let input = [0.0, 0.1, 0.2, 0.3, 0.4];
+        let mut out = Vec::new();
+        r.process(&input, |s| out.push(s));
+        assert_eq!(out.len(), input.len() - 1);
+        for (a, b) in out.iter().zip(input.iter()) {
+            assert!((a - b).abs() < 1e-6, "{a} vs {b}");
+        }
+    }
+
+    /// Upsampling 2x roughly doubles the output count and the midpoints interpolate.
+    #[test]
+    fn push_upsample_2x_interpolates_midpoints() {
+        let mut r = PushResampler::new(24_000, 48_000); // step = 0.5
+        let input = [0.0, 1.0, 2.0, 3.0];
+        let mut out = Vec::new();
+        r.process(&input, |s| out.push(s));
+        // (n - 1) segments at 2 outputs each = 6.
+        assert_eq!(out.len(), 6, "out {out:?}");
+        // A half-step between 1.0 and 2.0 must appear near 1.5.
+        assert!(
+            out.iter().any(|&s| (s - 1.5).abs() < 1e-3),
+            "expected a ~1.5 midpoint in {out:?}"
+        );
+    }
+
+    /// Downsampling drops the rate: fewer outputs than inputs, monotonic ramp preserved.
+    #[test]
+    fn push_downsample_reduces_count() {
+        let mut r = PushResampler::new(48_000, 44_100); // step ~1.088
+        let input: Vec<f32> = (0..441).map(|i| i as f32).collect();
+        let mut out = Vec::new();
+        r.process(&input, |s| out.push(s));
+        // 441 in @ 48k -> ~405 out @ 44.1k.
+        assert!(
+            (390..=410).contains(&out.len()),
+            "expected ~405 outputs, got {}",
+            out.len()
+        );
+        // Output stays within the input's value range and is non-decreasing.
+        for w in out.windows(2) {
+            assert!(w[1] >= w[0] - 1e-3, "ramp should not reverse: {w:?}");
+        }
+        assert!(*out.last().unwrap() <= 440.0 + 1e-3);
+    }
+
+    /// Pull resampler at equal rates returns each input frame in order, aligned.
+    /// Two-pull priming uses one frame of lookahead, so `n` inputs yield `n - 1`
+    /// outputs (the last frame emits once a successor arrives).
+    #[test]
+    fn pull_identity_when_rates_match() {
+        let mut r = StereoPullResampler::new(48_000, 48_000);
+        let frames = [(0.0, 9.0), (1.0, 8.0), (2.0, 7.0), (3.0, 6.0)];
+        let mut idx = 0;
+        let mut out = Vec::new();
+        while let Some(f) = r.next(|| {
+            let v = frames.get(idx).copied();
+            idx += 1;
+            v
+        }) {
+            out.push(f);
+        }
+        assert_eq!(out.len(), frames.len() - 1, "out {out:?}");
+        for (got, want) in out.iter().zip(frames.iter()) {
+            assert!((got.0 - want.0).abs() < 1e-6 && (got.1 - want.1).abs() < 1e-6);
+        }
+    }
+
+    /// Pull resampler reports underrun (`None`) once the source is exhausted.
+    #[test]
+    fn pull_returns_none_on_underrun() {
+        let mut r = StereoPullResampler::new(48_000, 44_100); // step ~1.088 -> pulls >1 per out
+        let frames = [(0.0, 0.0), (1.0, -1.0)];
+        let mut idx = 0;
+        let mut pull = || {
+            let v = frames.get(idx).copied();
+            idx += 1;
+            v
+        };
+        // First frame primes + emits; subsequent calls eventually exhaust the source.
+        let mut produced = 0;
+        let mut hit_none = false;
+        for _ in 0..10 {
+            if r.next(&mut pull).is_some() {
+                produced += 1;
+            } else {
+                hit_none = true;
+                break;
+            }
+        }
+        assert!(produced >= 1, "should produce at least the primed frame");
+        assert!(hit_none, "should report underrun once the puller is dry");
+    }
+
+    /// Downsampling via pull consumes more input frames than it emits output frames.
+    #[test]
+    fn pull_downsample_consumes_more_than_it_emits() {
+        let mut r = StereoPullResampler::new(48_000, 24_000); // step = 2.0
+        let input: Vec<(f32, f32)> = (0..100).map(|i| (i as f32, -(i as f32))).collect();
+        let mut idx = 0;
+        let mut emitted = 0;
+        for _ in 0..40 {
+            let f = r.next(|| {
+                let v = input.get(idx).copied();
+                idx += 1;
+                v
+            });
+            if f.is_some() {
+                emitted += 1;
+            } else {
+                break;
+            }
+        }
+        // At step 2.0 we consume ~2 input frames per output frame.
+        assert!(idx > emitted, "consumed {idx} input, emitted {emitted} output");
+    }
+
+    /// A zero rate must not produce a zero `step` (which would spin `push`'s inner
+    /// `while self.next < 1.0` forever). Clamping makes the call terminate (W7).
+    #[test]
+    fn push_zero_rate_does_not_spin() {
+        let mut r = PushResampler::new(0, 48_000);
+        let mut count = 0usize;
+        // Feed two samples; with a clamped non-zero step this returns promptly.
+        r.push(0.0, |_| count += 1);
+        r.push(1.0, |_| count += 1);
+        // Reaching here at all is the assertion (no hang); some output is produced.
+        assert!(count >= 1);
+    }
+
+    /// A zero output rate must not make the pull resampler's segment-advance loop
+    /// spin. Clamping keeps `step` finite so `next` terminates (W7).
+    #[test]
+    fn pull_zero_out_rate_does_not_spin() {
+        let mut r = StereoPullResampler::new(48_000, 0);
+        let frames = [(0.0, 0.0), (1.0, 1.0), (2.0, 2.0)];
+        let mut idx = 0;
+        let got = r.next(|| {
+            let v = frames.get(idx).copied();
+            idx += 1;
+            v
+        });
+        // Terminates and yields the primed frame instead of hanging.
+        assert!(got.is_some());
+    }
+}
@@ -0,0 +1,107 @@
+//! Custom UI background (W16): turn a user-picked image into a capped PNG to
+//! render behind the whole UI, plus the legibility scrim drawn over it.
+//!
+//! This is the pure, unit-testable seam — `process_background` decodes/downscales
+//! arbitrary input defensively (same caution as avatar uploads) and `scrim_color`
+//! computes the overlay tint. The file I/O, the `rfd` picker, and the iced
+//! `stack!` that layers image → scrim → UI all live at the app edge in
+//! `src/app/mod.rs`. The background is **local-only** — never sent to peers — so
+//! there's no gossip-frame budget here (hence a much larger size cap than avatars).
+
+use iced::Color;
+
+/// Longest side a custom background is downscaled to on ingest (aspect preserved,
+/// never upscaled). Big enough to look crisp filling the window, small enough to
+/// decode and cache cheaply. Local-only, so this is generous vs. the avatar cap.
+pub const BACKGROUND_MAX_PX: u32 = 1920;
+
+/// Default scrim strength. `0.0` = the image shows at full strength, `1.0` = it's
+/// fully hidden behind the theme's base colour. Half keeps a photo clearly visible
+/// while text and cards stay readable over it.
+pub const DEFAULT_DIM: f32 = 0.5;
+
+/// Decode an arbitrary user image (png/jpeg/…), downscale so its longest side is
+/// at most [`BACKGROUND_MAX_PX`] (aspect preserved; smaller images are left as-is,
+/// never upscaled), and re-encode as PNG bytes ready to write to disk. Decoding is
+/// bounded by the `image` crate's defaults so a malformed/huge file is rejected
+/// rather than exhausting memory. Errors come back as a message for the UI.
+pub fn process_background(raw: &[u8]) -> Result<Vec<u8>, String> {
+    let img = image::load_from_memory(raw).map_err(|e| format!("Couldn't read image: {e}"))?;
+    // Only ever shrink. `resize` preserves aspect, fitting within the box; a
+    // higher-quality filter than `thumbnail` since a background fills the window.
+    let scaled = if img.width() > BACKGROUND_MAX_PX || img.height() > BACKGROUND_MAX_PX {
+        img.resize(
+            BACKGROUND_MAX_PX,
+            BACKGROUND_MAX_PX,
+            image::imageops::FilterType::Lanczos3,
+        )
+    } else {
+        img
+    };
+    let mut png = std::io::Cursor::new(Vec::new());
+    scaled
+        .write_to(&mut png, image::ImageFormat::Png)
+        .map_err(|e| format!("Couldn't encode image: {e}"))?;
+    Ok(png.into_inner())
+}
+
+/// The legibility scrim drawn between the background image and the UI: the active
+/// theme's base colour at `dim` alpha (clamped to `0.0..=1.0`). A higher `dim`
+/// recedes the image so body text and panel chrome stay readable, and it re-tints
+/// per theme since `base` comes from the active palette.
+pub fn scrim_color(base: Color, dim: f32) -> Color {
+    Color { a: dim.clamp(0.0, 1.0), ..base }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// A valid PNG of the given size, as raw bytes (test helper).
+    fn make_png(w: u32, h: u32) -> Vec<u8> {
+        let img = image::DynamicImage::new_rgb8(w, h);
+        let mut buf = std::io::Cursor::new(Vec::new());
+        img.write_to(&mut buf, image::ImageFormat::Png).unwrap();
+        buf.into_inner()
+    }
+
+    #[test]
+    fn process_background_downscales_oversized() {
+        // A 4000x2000 image is shrunk so the longest side is BACKGROUND_MAX_PX,
+        // aspect preserved, and the result re-decodes as a PNG within bounds.
+        let raw = make_png(4000, 2000);
+        let png = process_background(&raw).expect("should process");
+        let decoded = image::load_from_memory(&png).unwrap();
+        assert_eq!(decoded.width().max(decoded.height()), BACKGROUND_MAX_PX);
+        assert_eq!(decoded.width(), BACKGROUND_MAX_PX);
+        assert_eq!(decoded.height(), BACKGROUND_MAX_PX / 2); // 2:1 aspect kept
+    }
+
+    #[test]
+    fn process_background_leaves_small_images_unscaled() {
+        let raw = make_png(640, 480);
+        let png = process_background(&raw).expect("should process");
+        let decoded = image::load_from_memory(&png).unwrap();
+        assert_eq!((decoded.width(), decoded.height()), (640, 480));
+    }
+
+    #[test]
+    fn process_background_rejects_non_image() {
+        assert!(process_background(b"definitely not an image").is_err());
+    }
+
+    #[test]
+    fn scrim_color_sets_alpha_and_keeps_rgb() {
+        let base = Color::from_rgb(0.1, 0.2, 0.3);
+        let s = scrim_color(base, 0.5);
+        assert_eq!((s.r, s.g, s.b), (0.1, 0.2, 0.3));
+        assert!((s.a - 0.5).abs() < f32::EPSILON);
+    }
+
+    #[test]
+    fn scrim_color_clamps_dim() {
+        let base = Color::BLACK;
+        assert!((scrim_color(base, -1.0).a - 0.0).abs() < f32::EPSILON);
+        assert!((scrim_color(base, 2.0).a - 1.0).abs() < f32::EPSILON);
+    }
+}
@@ -1,11 +1,11 @@
 //! Audio playout diagnostic probe.
 //!
-//! Drives a phase-continuous sine tone through the *real* PipeWire playback path
-//! (`PipeWireBackend::start_playback`), using the *same* fill-paced production
-//! the production mixer uses (`core/mod.rs`): generate a frame only while the
+//! Drives a phase-continuous sine tone through the *real* playback path
+//! (PipeWire on Linux, cpal/WASAPI on Windows), using the *same* fill-paced
+//! production the production mixer uses (`core/mod.rs`): generate a frame only while the
 //! playback ring is below `PLAYBACK_TARGET_SAMPLES`, so production tracks the
-//! PipeWire hardware clock. No network, no microphone — this isolates the local
-//! output path so we can confirm the clock-paced playout is glitch-free.
+//! hardware clock. No network, no microphone — this isolates the local output
+//! path so we can confirm the clock-paced playout is glitch-free.
 //!
 //! Use your ears on the tone (any click/pop is a glitch) together with the
 //! `playout-health:` lines tailed to stdout:
@@ -17,105 +17,235 @@
 //!
 //! Run:  cargo run --bin audio_probe -- [freq_hz] [seconds] [target_node]
 //!   e.g. cargo run --release --bin audio_probe -- 440 30
+//!
+//! This probe exercises the platform playback backend directly: PipeWire on Linux
+//! and cpal/WASAPI on Windows. Other targets use a stub that explains the limitation.

-use std::io::{BufRead, BufReader, Seek, SeekFrom};
-use std::sync::Arc;
-use std::sync::atomic::AtomicUsize;
-use std::sync::mpsc;
-use std::time::Duration;
-
-use peerspeak::audio::AudioBackend;
-use peerspeak::audio::pipewire_impl::PipeWireBackend;
-use peerspeak::core::jitter::FRAME_SAMPLES; // 960 mono frames = 20ms @ 48kHz
-
-const SAMPLE_RATE: f32 = 48_000.0;
-
-#[tokio::main]
-async fn main() {
-    let mut args = std::env::args().skip(1);
-    let freq: f32 = args.next().and_then(|s| s.parse().ok()).unwrap_or(440.0);
-    let secs: u64 = args.next().and_then(|s| s.parse().ok()).unwrap_or(30);
-    let target_node: Option<String> = args.next();
-
-    // The playout-health logger is quiet in normal operation (it only logs
-    // glitches); ask it for the full once-per-second heartbeat so the probe can
-    // show the steady-state numbers.
-    // SAFETY: set before any playback thread starts, so no concurrent env read.
-    unsafe { std::env::set_var("PEERSPEAK_AUDIO_VERBOSE", "1") };
-
-    println!("audio_probe: {freq} Hz tone for {secs}s through the real playback path.");
-    println!("Listen for clicks/pops; watch the playout-health lines below.\n");
-
-    // Tail the app log (where playout-health lines land) to stdout in the
-    // background so it's all in one terminal.
-    spawn_log_tailer();
-
-    let backend = PipeWireBackend::new();
-    let (tx, rx) = mpsc::channel::<Vec<i16>>();
-    let ring_fill = Arc::new(AtomicUsize::new(0));
-    if let Err(e) = backend.start_playback(rx, target_node, ring_fill.clone()) {
-        eprintln!("failed to start playback: {e}");
-        return;
-    }
-
-    // Phase-continuous sine, generated one 20ms frame at a time, fill-paced
-    // exactly like the production mixer: only produce while the ring is below
-    // target, so production tracks the PipeWire hardware clock.
-    use std::sync::atomic::Ordering;
-    let deadline = tokio::time::Instant::now() + Duration::from_secs(secs);
-    let mut n: u64 = 0; // running sample index keeps phase continuous across frames
-    while tokio::time::Instant::now() < deadline {
-        if ring_fill.load(Ordering::Relaxed) >= peerspeak::audio::PLAYBACK_TARGET_SAMPLES {
-            tokio::time::sleep(Duration::from_millis(2)).await;
-            continue;
-        }
-        let mut frame = Vec::with_capacity(FRAME_SAMPLES * peerspeak::audio::PLAYBACK_CHANNELS);
-        for _ in 0..FRAME_SAMPLES {
-            let t = n as f32 / SAMPLE_RATE;
-            // 0.25 amplitude: clearly audible but not harsh.
-            let sample = (0.25 * i16::MAX as f32 * (2.0 * std::f32::consts::PI * freq * t).sin()) as i16;
-            // Stereo playback bus: duplicate the probe tone to L/R.
-            frame.push(sample);
-            frame.push(sample);
-            n += 1;
-        }
-        if tx.send(frame).is_err() {
-            eprintln!("playback channel closed early");
-            break;
-        }
-    }
-
-    // Let the ring drain, then stop.
-    tokio::time::sleep(Duration::from_millis(300)).await;
-    let _ = backend.stop();
-    println!("\naudio_probe: done.");
+#[cfg(target_os = "linux")]
+fn main() {
+    unix_probe::run();
 }

-/// Open the app log, seek to the end, and echo new lines (the `playout-health:`
-/// reports) to stdout once they appear.
-fn spawn_log_tailer() {
-    let path = peerspeak::log_file_path();
-    std::thread::spawn(move || {
-        // Wait for the file to exist (first log_msg creates it).
-        let file = loop {
-            if let Ok(f) = std::fs::File::open(&path) {
-                break f;
+#[cfg(windows)]
+fn main() {
+    win_probe::run();
+}
+
+#[cfg(not(any(target_os = "linux", windows)))]
+fn main() {
+    eprintln!(
+        "audio_probe is only supported on Linux and Windows builds (it drives the platform playback backend directly)."
+    );
+}
+
+#[cfg(target_os = "linux")]
+mod unix_probe {
+    use std::io::{BufRead, BufReader, Seek, SeekFrom};
+    use std::sync::Arc;
+    use std::sync::atomic::AtomicUsize;
+    use std::sync::mpsc;
+    use std::time::Duration;
+
+    use peerspeak::audio::AudioBackend;
+    use peerspeak::audio::pipewire_impl::PipeWireBackend;
+    use peerspeak::core::jitter::FRAME_SAMPLES; // 960 mono frames = 20ms @ 48kHz
+
+    const SAMPLE_RATE: f32 = 48_000.0;
+
+    #[tokio::main]
+    pub async fn run() {
+        let mut args = std::env::args().skip(1);
+        let freq: f32 = args.next().and_then(|s| s.parse().ok()).unwrap_or(440.0);
+        let secs: u64 = args.next().and_then(|s| s.parse().ok()).unwrap_or(30);
+        let target_node: Option<String> = args.next();
+
+        // The playout-health logger is quiet in normal operation (it only logs
+        // glitches); ask it for the full once-per-second heartbeat so the probe can
+        // show the steady-state numbers.
+        // SAFETY: set before any playback thread starts, so no concurrent env read.
+        unsafe { std::env::set_var("PEERSPEAK_AUDIO_VERBOSE", "1") };
+
+        println!("audio_probe: {freq} Hz tone for {secs}s through the real playback path.");
+        println!("Listen for clicks/pops; watch the playout-health lines below.\n");
+
+        // Tail the app log (where playout-health lines land) to stdout in the
+        // background so it's all in one terminal.
+        spawn_log_tailer();
+
+        let backend = PipeWireBackend::new();
+        let (tx, rx) = mpsc::channel::<Vec<i16>>();
+        let ring_fill = Arc::new(AtomicUsize::new(0));
+        if let Err(e) = backend.start_playback(rx, target_node, ring_fill.clone()) {
+            eprintln!("failed to start playback: {e}");
+            return;
+        }
+
+        // Phase-continuous sine, generated one 20ms frame at a time, fill-paced
+        // exactly like the production mixer: only produce while the ring is below
+        // target, so production tracks the PipeWire hardware clock.
+        use std::sync::atomic::Ordering;
+        let deadline = tokio::time::Instant::now() + Duration::from_secs(secs);
+        let mut n: u64 = 0; // running sample index keeps phase continuous across frames
+        while tokio::time::Instant::now() < deadline {
+            if ring_fill.load(Ordering::Relaxed) >= peerspeak::audio::PLAYBACK_TARGET_SAMPLES {
+                tokio::time::sleep(Duration::from_millis(2)).await;
+                continue;
            }
-            std::thread::sleep(Duration::from_millis(100));
-        };
-        let mut reader = BufReader::new(file);
-        let _ = reader.seek(SeekFrom::End(0));
-        loop {
-            let mut line = String::new();
-            match reader.read_line(&mut line) {
-                Ok(0) => std::thread::sleep(Duration::from_millis(150)),
-                Ok(_) => {
-                    if line.contains("playout-health:") {
-                        print!("{line}");
-                    }
+            let mut frame = Vec::with_capacity(FRAME_SAMPLES * peerspeak::audio::PLAYBACK_CHANNELS);
+            for _ in 0..FRAME_SAMPLES {
+                let t = n as f32 / SAMPLE_RATE;
+                // 0.25 amplitude: clearly audible but not harsh.
+                let sample =
+                    (0.25 * i16::MAX as f32 * (2.0 * std::f32::consts::PI * freq * t).sin()) as i16;
+                // Stereo playback bus: duplicate the probe tone to L/R.
+                frame.push(sample);
+                frame.push(sample);
+                n += 1;
+            }
+            if tx.send(frame).is_err() {
+                eprintln!("playback channel closed early");
+                break;
+            }
+        }
+
+        // Let the ring drain, then stop.
+        tokio::time::sleep(Duration::from_millis(300)).await;
+        let _ = backend.stop();
+        println!("\naudio_probe: done.");
+    }
+
+    /// Open the app log, seek to the end, and echo new lines (the `playout-health:`
+    /// reports) to stdout once they appear.
+    fn spawn_log_tailer() {
+        let path = peerspeak::log_file_path();
+        std::thread::spawn(move || {
+            // Wait for the file to exist (first log_msg creates it).
+            let file = loop {
+                if let Ok(f) = std::fs::File::open(&path) {
+                    break f;
                }
-                Err(_) => std::thread::sleep(Duration::from_millis(150)),
+                std::thread::sleep(Duration::from_millis(100));
+            };
+            let mut reader = BufReader::new(file);
+            let _ = reader.seek(SeekFrom::End(0));
+            loop {
+                let mut line = String::new();
+                match reader.read_line(&mut line) {
+                    Ok(0) => std::thread::sleep(Duration::from_millis(150)),
+                    Ok(_) => {
+                        if line.contains("playout-health:") {
+                            print!("{line}");
+                        }
+                    }
+                    Err(_) => std::thread::sleep(Duration::from_millis(150)),
+                }
+            }
+        });
+    }
+}
+
+#[cfg(windows)]
+mod win_probe {
+    use std::io::{BufRead, BufReader, Seek, SeekFrom};
+    use std::sync::Arc;
+    use std::sync::atomic::AtomicUsize;
+    use std::sync::mpsc;
+    use std::time::Duration;
+
+    use peerspeak::audio::AudioBackend;
+    use peerspeak::audio::cpal_impl::CpalBackend;
+    use peerspeak::core::jitter::FRAME_SAMPLES; // 960 mono frames = 20ms @ 48kHz
+
+    const SAMPLE_RATE: f32 = 48_000.0;
+
+    #[tokio::main]
+    pub async fn run() {
+        let mut args = std::env::args().skip(1);
+        let freq: f32 = args.next().and_then(|s| s.parse().ok()).unwrap_or(440.0);
+        let secs: u64 = args.next().and_then(|s| s.parse().ok()).unwrap_or(30);
+        let target_node: Option<String> = args.next();
+
+        // The playout-health logger is quiet in normal operation (it only logs
+        // glitches); ask it for the full once-per-second heartbeat so the probe can
+        // show the steady-state numbers.
+        // SAFETY: set before any playback thread starts, so no concurrent env read.
+        unsafe { std::env::set_var("PEERSPEAK_AUDIO_VERBOSE", "1") };
+
+        println!("audio_probe: {freq} Hz tone for {secs}s through the real playback path.");
+        println!("Listen for clicks/pops; watch the playout-health lines below.\n");
+
+        // Tail the app log (where playout-health lines land) to stdout in the
+        // background so it's all in one terminal.
+        spawn_log_tailer();
+
+        let backend = CpalBackend::new();
+        let (tx, rx) = mpsc::channel::<Vec<i16>>();
+        let ring_fill = Arc::new(AtomicUsize::new(0));
+        if let Err(e) = backend.start_playback(rx, target_node, ring_fill.clone()) {
+            eprintln!("failed to start playback: {e}");
+            return;
+        }
+
+        // Phase-continuous sine, generated one 20ms frame at a time, fill-paced
+        // exactly like the production mixer: only produce while the ring is below
+        // target, so production tracks the cpal/WASAPI hardware clock.
+        use std::sync::atomic::Ordering;
+        let deadline = tokio::time::Instant::now() + Duration::from_secs(secs);
+        let mut n: u64 = 0; // running sample index keeps phase continuous across frames
+        while tokio::time::Instant::now() < deadline {
+            if ring_fill.load(Ordering::Relaxed) >= peerspeak::audio::PLAYBACK_TARGET_SAMPLES {
+                tokio::time::sleep(Duration::from_millis(2)).await;
+                continue;
+            }
+            let mut frame = Vec::with_capacity(FRAME_SAMPLES * peerspeak::audio::PLAYBACK_CHANNELS);
+            for _ in 0..FRAME_SAMPLES {
+                let t = n as f32 / SAMPLE_RATE;
+                // 0.25 amplitude: clearly audible but not harsh.
+                let sample =
+                    (0.25 * i16::MAX as f32 * (2.0 * std::f32::consts::PI * freq * t).sin()) as i16;
+                // Stereo playback bus: duplicate the probe tone to L/R.
+                frame.push(sample);
+                frame.push(sample);
+                n += 1;
+            }
+            if tx.send(frame).is_err() {
+                eprintln!("playback channel closed early");
+                break;
            }
        }
-    });
+
+        // Let the ring drain, then stop.
+        tokio::time::sleep(Duration::from_millis(300)).await;
+        let _ = backend.stop();
+        println!("\naudio_probe: done.");
+    }
+
+    /// Open the app log, seek to the end, and echo new lines (the `playout-health:`
+    /// reports) to stdout once they appear.
+    fn spawn_log_tailer() {
+        let path = peerspeak::log_file_path();
+        std::thread::spawn(move || {
+            // Wait for the file to exist (first log_msg creates it).
+            let file = loop {
+                if let Ok(f) = std::fs::File::open(&path) {
+                    break f;
+                }
+                std::thread::sleep(Duration::from_millis(100));
+            };
+            let mut reader = BufReader::new(file);
+            let _ = reader.seek(SeekFrom::End(0));
+            loop {
+                let mut line = String::new();
+                match reader.read_line(&mut line) {
+                    Ok(0) => std::thread::sleep(Duration::from_millis(150)),
+                    Ok(_) => {
+                        if line.contains("playout-health:") {
+                            print!("{line}");
+                        }
+                    }
+                    Err(_) => std::thread::sleep(Duration::from_millis(150)),
+                }
+            }
+        });
+    }
 }
@@ -106,6 +106,10 @@ fn default_true() -> bool {
    true
 }

+fn default_background_dim() -> f32 {
+    crate::background::DEFAULT_DIM
+}
+
 fn default_volume() -> f32 {
    1.0
 }
@@ -185,6 +189,16 @@ pub struct AppConfig {
    /// Our chosen avatar (W4): monogram fallback or a bundled preset.
    #[serde(default)]
    pub avatar: crate::avatar::Avatar,
+    /// Custom UI background image (W16): path to the downscaled PNG we wrote into
+    /// the config dir (see `background_path`). `None` = use the theme background.
+    /// Local-only; never sent to peers.
+    #[serde(default)]
+    pub background: Option<String>,
+    /// Scrim strength drawn over the custom background for legibility (0.0 = image
+    /// at full strength, 1.0 = fully hidden behind the theme base). See
+    /// `crate::background::scrim_color`.
+    #[serde(default = "default_background_dim")]
+    pub background_dim: f32,
    /// What a call recording captures (mixed / per-peer stems / both).
    #[serde(default)]
    pub recording_mode: RecordingMode,
@@ -241,6 +255,15 @@ pub struct AppConfig {
    /// keyed by peer node id string. Local preference only.
    #[serde(default)]
    pub peer_pan: HashMap<String, f32>,
+    /// Per-peer listener-side volume/gain (`1.0` = unity), keyed by peer node id
+    /// string. Local preference only; never sent to peers. Absent entry = unity.
+    #[serde(default)]
+    pub peer_volume: HashMap<String, f32>,
+    /// Per-peer listener-side noise-gate threshold (normalized RMS, `0.0` = off),
+    /// keyed by peer node id string. Local preference only; never sent to peers.
+    /// Absent entry = gate disabled (pass-through).
+    #[serde(default)]
+    pub peer_gate: HashMap<String, f32>,
    /// Focused app-local keyboard shortcuts.
    #[serde(default)]
    pub hotkeys: crate::hotkeys::HotkeyMap,
@@ -280,6 +303,8 @@ impl Default for AppConfig {
            room_layout: RoomLayout::default(),
            theme: AppTheme::default(),
            avatar: crate::avatar::Avatar::default(),
+            background: None,
+            background_dim: default_background_dim(),
            recording_mode: RecordingMode::default(),
            custom_sound_self_join: None,
            custom_sound_peer_join: None,
@@ -301,6 +326,8 @@ impl Default for AppConfig {
            recents: Vec::new(),
            peer_eq: HashMap::new(),
            peer_pan: HashMap::new(),
+            peer_volume: HashMap::new(),
+            peer_gate: HashMap::new(),
            hotkeys: crate::hotkeys::HotkeyMap::default(),
            window_width: default_window_width(),
            window_height: default_window_height(),
@@ -348,6 +375,17 @@ impl AppConfig {
        })
    }

+    /// Path the processed custom-background PNG (W16) is written to, alongside
+    /// `config.json` in the app config dir. We store our own downscaled copy here
+    /// (rather than base64 in the config) so the JSON stays small.
+    pub fn background_path() -> Option<PathBuf> {
+        dirs::config_dir().map(|mut p| {
+            p.push("peerspeak");
+            p.push("background.png");
+            p
+        })
+    }
+
    pub fn load() -> Self {
        if let Some(path) = Self::config_path()
            && let Ok(contents) = fs::read_to_string(&path)
@@ -430,6 +468,8 @@ mod tests {
        // shortcut settings.
        assert!(deserialized.peer_eq.is_empty());
        assert!(deserialized.peer_pan.is_empty());
+        assert!(deserialized.peer_volume.is_empty());
+        assert!(deserialized.peer_gate.is_empty());
        assert_eq!(
            crate::hotkeys::format_binding(
                deserialized
@@ -26,6 +26,10 @@ pub enum CoreCommand {
    SetPeerEq(EndpointId, crate::audio::eq::EqSettings),
    /// Listener-side per-peer pan. Local only; never leaves this app instance.
    SetPeerPan(EndpointId, f32),
+    /// Listener-side per-peer noise gate threshold (normalized RMS, `0.0` = off).
+    /// Applies the same smooth gate as the mic path to a peer's incoming audio,
+    /// to suppress their background noise on our end. Local only.
+    SetPeerGate(EndpointId, f32),
    /// Locally mute/unmute a peer: when muted, their audio is decoded (so levels
    /// still show) but not mixed into our output.
    SetPeerMuted(EndpointId, bool),
@@ -49,6 +53,14 @@ pub enum CoreCommand {
    SetRecordingMode(RecordingMode),
    /// Broadcast a room text-chat message. No-op when not in a call.
    SendChat(String),
+    /// Send a chat message carrying a file attachment. The app has already read +
+    /// capped the file and built the descriptor; core makes the bytes available
+    /// on the file plane and broadcasts the descriptor.
+    SendChatFile { text: String, attachment: crate::files::ChatAttachment, data: Vec<u8> },
+    /// Fetch a received attachment's bytes from its sender over the file plane
+    /// (used for on-demand file/chip downloads; images are auto-fetched on
+    /// receipt). Replies with `AttachmentReady`/`AttachmentFailed`.
+    FetchAttachment { from: EndpointId, attachment: crate::files::ChatAttachment },
    /// Set the pixelpass binary location (config override, empty = use `$PATH`).
    /// Sent at startup so screen-share can resolve the binary.
    SetPixelpassPath(Option<String>),
@@ -85,6 +97,9 @@ pub enum UiEvent {
    RoomLeft,
    PeerJoined { id: EndpointId, state: PeerState },
    PeerLeft { id: EndpointId },
+    /// The fixed reconnect grace expired and bounded background gossip recovery
+    /// has started. This is non-terminal and must not play the failure chime.
+    PeerRecoveryStarted { id: EndpointId },
    PeerConnectionFailed { id: EndpointId },
    PeerUpdated { id: EndpointId, state: PeerState },
    /// Audio link to a peer is being (re)established — show a connecting state.
@@ -102,7 +117,13 @@ pub enum UiEvent {
    /// A room text-chat message arrived from a peer (never our own — local
    /// messages are echoed by the UI on send). `from` is the sender's node id
    /// string, used to key their avatar (W4).
-    ChatMessage { from: String, name: String, text: String },
+    ChatMessage { from: String, name: String, text: String, attachment: Option<crate::files::ChatAttachment> },
+    /// An attachment's bytes are now available (auto-fetched for images, or
+    /// fetched on demand for files). Keyed by attachment id so the UI can match
+    /// it to the chat entry.
+    AttachmentReady { id: crate::files::AttachmentId, data: Vec<u8> },
+    /// An attachment fetch failed (sender gone, too large, decode error, etc.).
+    AttachmentFailed { id: crate::files::AttachmentId, error: String },
    /// Our own screen share started; the UI flips the Share button to "Stop".
    ScreenShareStarted,
    /// Our own screen share stopped (or failed to start).
@@ -1,16 +1,18 @@
 pub mod messages;
 pub mod jitter;
+mod recovery;

-use crate::audio::{AudioBackend, pipewire_impl::PipeWireBackend};
+use crate::audio::{AudioBackend, PlatformAudioBackend};
 use crate::audio::eq::{Eq, EqSettings};
 use crate::codec::{AudioEncoder, opus_impl::OpusEncoder};
 use crate::core::jitter::{JitterBuffer, FRAME_SAMPLES};
 use crate::network::{
    NetworkTransport, RoomState, PeerState, RoomEvent, ConnEvent, PeerSpeakTicket,
-    iroh_impl::{IrohTransport, AudioRouter},
+    iroh_impl::{IrohTransport, AudioRouter, FileRouter},
    gossip::IrohGossipState,
 };
 use crate::core::messages::{CoreCommand, UiEvent};
+use crate::core::recovery::RecoveryCoordinator;

 use crate::config::{NetworkMode, RecordingMode};
 use crate::presence::PresenceMode;
@@ -102,6 +104,39 @@ type GraceTimers = Arc<std::sync::Mutex<HashMap<EndpointId, tokio::task::JoinHan
 /// Scrubbed whenever a peer is evicted or leaves so a later rejoin starts clean.
 type SeenConnected = Arc<std::sync::Mutex<HashSet<EndpointId>>>;

+type KnownPeers =
+    Arc<std::sync::Mutex<HashMap<String, HashMap<EndpointId, EndpointAddr>>>>;
+
+#[derive(Clone)]
+struct RecoveryContext {
+    coordinator: RecoveryCoordinator,
+    room_state: Arc<IrohGossipState>,
+    known_peers: KnownPeers,
+    ticket: String,
+}
+
+impl RecoveryContext {
+    fn retained_addr(&self, peer_id: &EndpointId) -> Option<EndpointAddr> {
+        self.known_peers
+            .lock()
+            .unwrap()
+            .get(&self.ticket)
+            .and_then(|peers| peers.get(peer_id))
+            .cloned()
+    }
+
+    fn cancel(&self, peer_id: EndpointId) {
+        self.coordinator.cancel(peer_id);
+    }
+
+    fn forget(&self, peer_id: EndpointId) {
+        if let Some(peers) = self.known_peers.lock().unwrap().get_mut(&self.ticket) {
+            peers.remove(&peer_id);
+        }
+        self.coordinator.cancel(peer_id);
+    }
+}
+
 /// Cancel and forget a peer's pending grace timer, if any. No-op if none is armed.
 fn cancel_grace_timer(timers: &GraceTimers, peer_id: &EndpointId) {
    if let Some(handle) = timers.lock().unwrap().remove(peer_id) {
@@ -116,12 +151,17 @@ fn cancel_grace_timer(timers: &GraceTimers, peer_id: &EndpointId) {
 /// link repeatedly resetting the clock and dodging eviction forever. On firing it
 /// also scrubs the peer from `seen_connected` so a later rejoin isn't treated as a
 /// reconnect on its initial dial.
+struct GraceExpiry<'a> {
+    transport: &'a Arc<IrohTransport>,
+    jitter: &'a Arc<Mutex<HashMap<EndpointId, JitterBuffer>>>,
+    ui_tx: &'a mpsc::Sender<UiEvent>,
+    recovery: Option<&'a RecoveryContext>,
+}
+
 fn arm_grace_timer(
    timers: &GraceTimers,
    seen_connected: &SeenConnected,
-    transport: &Arc<IrohTransport>,
-    jitter: &Arc<Mutex<HashMap<EndpointId, JitterBuffer>>>,
-    ui_tx: &mpsc::Sender<UiEvent>,
+    expiry: GraceExpiry<'_>,
    grace: Duration,
    peer_id: EndpointId,
 ) {
@@ -129,15 +169,29 @@ fn arm_grace_timer(
    if timers_guard.contains_key(&peer_id) {
        return;
    }
-    let transport_evict = transport.clone();
-    let jitter_evict = jitter.clone();
-    let ui_evict = ui_tx.clone();
+    let transport_evict = expiry.transport.clone();
+    let jitter_evict = expiry.jitter.clone();
+    let ui_evict = expiry.ui_tx.clone();
    let timers_evict = timers.clone();
    let seen_evict = seen_connected.clone();
+    let recovery_evict = expiry.recovery.cloned();
    let handle = tokio::spawn(async move {
        tokio::time::sleep(grace).await;
-        crate::log_msg(&format!("Reconnect grace expired; evicting peer {:?}", peer_id));
+        crate::log_msg(&format!("Reconnect grace expired for peer {:?}", peer_id));
+
+        if let Some(recovery) = &recovery_evict
+            && !recovery.coordinator.begin(peer_id)
+        {
+            return;
+        }
+
        transport_evict.remove_audio_sender(peer_id);
+        if let Some(recovery) = &recovery_evict {
+            // Revoke roster authority before the first await in teardown. A
+            // verified Announce racing after this point is then a PeerJoined and
+            // cancels recovery instead of being erased after it was accepted.
+            recovery.room_state.mark_peer_disconnected(peer_id);
+        }
        transport_evict.disconnect_peer(peer_id).await;
        jitter_evict.lock().await.remove(&peer_id);
        // Scrub our internal state *before* announcing the eviction, so anything
@@ -146,7 +200,38 @@ fn arm_grace_timer(
        // reconnect.
        timers_evict.lock().unwrap().remove(&peer_id);
        seen_evict.lock().unwrap().remove(&peer_id);
-        let _ = ui_evict.send(UiEvent::PeerConnectionFailed { id: peer_id }).await;
+
+        let Some(recovery) = recovery_evict else {
+            let _ = ui_evict.send(UiEvent::PeerConnectionFailed { id: peer_id }).await;
+            return;
+        };
+        if !recovery.coordinator.is_active(&peer_id) {
+            return;
+        }
+
+        let Some(addr) = recovery.retained_addr(&peer_id) else {
+            crate::log_msg(&format!(
+                "Cannot recover peer {:?}: no retained authenticated address",
+                peer_id
+            ));
+            recovery.cancel(peer_id);
+            let _ = ui_evict.send(UiEvent::PeerConnectionFailed { id: peer_id }).await;
+            return;
+        };
+
+        match recovery.coordinator.activate(peer_id, addr) {
+            Ok(true) => {
+                let _ = ui_evict.send(UiEvent::PeerRecoveryStarted { id: peer_id }).await;
+            }
+            Ok(false) => {}
+            Err(()) => {
+                crate::log_msg(&format!(
+                    "Cannot recover peer {:?}: recovery coordinator unavailable",
+                    peer_id
+                ));
+                let _ = ui_evict.send(UiEvent::PeerConnectionFailed { id: peer_id }).await;
+            }
+        }
    });
    timers_guard.insert(peer_id, handle);
 }
@@ -237,7 +322,7 @@ fn run_mic_monitor(
 /// Stops a standalone mic monitor if one is running. MUST NOT be called while a
 /// room session is active — `backend.stop()` would also tear down the call's
 /// capture/playback. Monitor and session are mutually exclusive by construction.
-fn stop_mic_monitor(backend: &PipeWireBackend, monitor: Option<MicMonitor>) {
+fn stop_mic_monitor(backend: &PlatformAudioBackend, monitor: Option<MicMonitor>) {
    if let Some(m) = monitor {
        let _ = backend.stop();
        let _ = m.thread.join();
@@ -309,6 +394,7 @@ pub struct ConnEventHandler {
    seen_connected: SeenConnected,
    transport: Arc<IrohTransport>,
    jitter: Arc<Mutex<HashMap<EndpointId, JitterBuffer>>>,
+    recovery: Option<RecoveryContext>,
    grace: Duration,
 }

@@ -326,6 +412,7 @@ impl ConnEventHandler {
            seen_connected,
            transport,
            jitter,
+            recovery: None,
            grace: RECONNECT_GRACE,
        }
    }
@@ -336,6 +423,11 @@ impl ConnEventHandler {
        self
    }

+    fn with_recovery(mut self, recovery: RecoveryContext) -> Self {
+        self.recovery = Some(recovery);
+        self
+    }
+
    pub async fn handle(&self, event: ConnEvent) {
        match event {
            ConnEvent::Connecting(id) => {
@@ -349,9 +441,12 @@ impl ConnEventHandler {
                    arm_grace_timer(
                        &self.grace_timers,
                        &self.seen_connected,
-                        &self.transport,
-                        &self.jitter,
-                        &self.ui_tx,
+                        GraceExpiry {
+                            transport: &self.transport,
+                            jitter: &self.jitter,
+                            ui_tx: &self.ui_tx,
+                            recovery: self.recovery.as_ref(),
+                        },
                        self.grace,
                        id,
                    );
@@ -359,6 +454,15 @@ impl ConnEventHandler {
                let _ = self.ui_tx.send(UiEvent::PeerConnecting { id }).await;
            }
            ConnEvent::Connected(id) => {
+                // A transport event cannot readmit a grace-expired peer. Ignore a
+                // stale/racing link until authenticated gossip emits PeerJoined.
+                if self
+                    .recovery
+                    .as_ref()
+                    .is_some_and(|recovery| recovery.coordinator.is_active(&id))
+                {
+                    return;
+                }
                // The audio link came back — the peer recovered within the grace
                // window, so cancel its eviction.
                cancel_grace_timer(&self.grace_timers, &id);
@@ -371,6 +475,9 @@ impl ConnEventHandler {
                // until the grace timer or the slow gossip Leave.
                cancel_grace_timer(&self.grace_timers, &id);
                self.seen_connected.lock().unwrap().remove(&id);
+                if let Some(recovery) = &self.recovery {
+                    recovery.forget(id);
+                }
                self.transport.remove_audio_sender(id);
                self.transport.disconnect_peer(id).await;
                self.jitter.lock().await.remove(&id);
@@ -387,9 +494,11 @@ struct ActiveSession {
    mixer_task: tokio::task::JoinHandle<()>,
    event_task: tokio::task::JoinHandle<()>,
    conn_event_task: tokio::task::JoinHandle<()>,
+    recovery_task: tokio::task::JoinHandle<()>,
    grace_timers: GraceTimers,
    transport: Arc<IrohTransport>,
    /// Loaded PipeWire echo-cancel module (if enabled); unloads on drop.
+    #[cfg(target_os = "linux")]
    echo_cancel: Option<crate::audio::echo_cancel::EchoCancelGuard>,
    /// Our pixelpass screen-share host child while sharing (`kill_on_drop`, so it
    /// also dies if the session is dropped without an explicit stop).
@@ -400,7 +509,7 @@ struct ActiveSession {
 }

 impl ActiveSession {
-    async fn shutdown(mut self, audio_backend: Arc<PipeWireBackend>) {
+    async fn shutdown(mut self, audio_backend: Arc<PlatformAudioBackend>) {
        crate::log_msg("ActiveSession::shutdown started");
        // Tear down any screen-share children first so the host stops streaming
        // promptly (kill_on_drop is the backstop, but kill explicitly so viewers
@@ -420,6 +529,7 @@ impl ActiveSession {
        for (_, handle) in self.grace_timers.lock().unwrap().drain() {
            handle.abort();
        }
+        self.recovery_task.abort();
        crate::log_msg("Aborted tasks");

        let audio_backend_clone = audio_backend.clone();
@@ -431,6 +541,7 @@ impl ActiveSession {

        // Unload the echo-cancel module now that the audio streams releasing its
        // virtual nodes have stopped. (Dropping the guard runs `pactl unload`.)
+        #[cfg(target_os = "linux")]
        drop(self.echo_cancel);

        crate::log_msg("Leaving room...");
@@ -467,6 +578,9 @@ struct NetStack {
    /// The persistent inbound-audio handler on `router`; per-join we bind the
    /// active session's transport into it, and clear it on leave.
    audio_router: AudioRouter,
+    /// The persistent chat-file-transfer handler on `router`; bound/cleared in
+    /// lock-step with `audio_router` (same session lifecycle).
+    file_router: FileRouter,
    /// In-memory address book (ticket + gossip fed), shared with every session.
    memory_lookup: iroh::address_lookup::memory::MemoryLookup,
 }
@@ -578,6 +692,7 @@ async fn build_net_stack(
        .spawn(endpoint.clone());

    let audio_router = AudioRouter::new();
+    let file_router = FileRouter::new();
    // The friends presence listener (W7 B2) rides this same persistent router as a
    // third ALPN — it MUST be a handler here, not a standalone accept loop, since
    // the router owns endpoint.accept(). Policy (who we answer / what room we
@@ -585,6 +700,7 @@ async fn build_net_stack(
    let router = Router::builder(endpoint.clone())
        .accept(iroh_gossip::net::GOSSIP_ALPN, gossip.clone())
        .accept(crate::protocol::AUDIO_ALPN, audio_router.clone())
+        .accept(crate::protocol::FILES_ALPN, file_router.clone())
        .accept(
            crate::presence_net::FRIENDS_ALPN,
            crate::presence_net::FriendsProtocol::new(friends_handler),
@@ -596,10 +712,49 @@ async fn build_net_stack(
        gossip,
        router,
        audio_router,
+        file_router,
        memory_lookup,
    })
 }

+/// Fetch a chat attachment's bytes from `from` over the file plane in a detached
+/// task, then report the result to the UI via [`UiEvent::AttachmentReady`] /
+/// [`UiEvent::AttachmentFailed`] keyed by the attachment id. For images
+/// (`is_image`) the bytes are defensively re-validated (decodable + within pixel
+/// limits) before being handed to the renderer; an "Image" that doesn't decode is
+/// reported as a failure rather than rendered.
+fn spawn_attachment_fetch(
+    transport: Arc<IrohTransport>,
+    ui_tx: mpsc::Sender<UiEvent>,
+    from: EndpointId,
+    att: crate::files::ChatAttachment,
+    is_image: bool,
+) {
+    tokio::spawn(async move {
+        match transport.fetch_attachment(from, &att).await {
+            Ok(data) => {
+                if is_image && crate::files::validate_image_bytes(&data).is_none() {
+                    let _ = ui_tx
+                        .send(UiEvent::AttachmentFailed {
+                            id: att.id,
+                            error: "received image failed to decode".to_string(),
+                        })
+                        .await;
+                    return;
+                }
+                let _ = ui_tx
+                    .send(UiEvent::AttachmentReady { id: att.id, data })
+                    .await;
+            }
+            Err(e) => {
+                let _ = ui_tx
+                    .send(UiEvent::AttachmentFailed { id: att.id, error: e.to_string() })
+                    .await;
+            }
+        }
+    });
+}
+
 /// Finalize and clear the active recording, if any, emitting `RecordingStopped`.
 /// No-op when not recording. Called on stop, room leave, and room switch so a
 /// recording is always closed cleanly (its WAV size fields patched).
@@ -728,10 +883,9 @@ async fn run_core_loop(
    // first room's peers — the old single-set version cleared them on any ticket
    // change, so an A→B→A bounce stranded the rejoiner with an empty bootstrap.
    // Inner map keyed by peer id so updates refresh the address.
-    let known_peers: Arc<std::sync::Mutex<HashMap<String, HashMap<EndpointId, EndpointAddr>>>> =
-        Arc::new(std::sync::Mutex::new(HashMap::new()));
+    let known_peers: KnownPeers = Arc::new(std::sync::Mutex::new(HashMap::new()));

-    let audio_backend = Arc::new(PipeWireBackend::new());
+    let audio_backend = Arc::new(PlatformAudioBackend::new());

    let is_muted = Arc::new(AtomicBool::new(false));
    let is_deafened = Arc::new(AtomicBool::new(false));
@@ -759,6 +913,8 @@ async fn run_core_loop(
    let peer_volumes = Arc::new(Mutex::new(HashMap::<EndpointId, f32>::new()));
    let peer_eq = Arc::new(Mutex::new(HashMap::<EndpointId, EqSettings>::new()));
    let peer_pan = Arc::new(Mutex::new(HashMap::<EndpointId, f32>::new()));
+    // Listener-side per-peer noise-gate thresholds (normalized RMS, 0.0 = off).
+    let peer_gate = Arc::new(Mutex::new(HashMap::<EndpointId, f32>::new()));
    // Peers locally muted by us: decoded for level metering but not mixed.
    let locally_muted = Arc::new(Mutex::new(HashSet::<EndpointId>::new()));
    let mut current_name = "Anonymous".to_string();
@@ -959,6 +1115,7 @@ async fn run_core_loop(
                if let Some(session) = active_session.take() {
                    session.shutdown(audio_backend.clone()).await;
                    net.audio_router.clear();
+                    net.file_router.clear();
                }
                *current_room.lock().unwrap() = None;

@@ -981,6 +1138,7 @@ async fn run_core_loop(
                    crate::log_msg("Shutting down existing active session");
                    session.shutdown(audio_backend.clone()).await;
                    net.audio_router.clear();
+                    net.file_router.clear();
                }

                // If a network-mode / identity change was deferred while a call was
@@ -1037,6 +1195,7 @@ async fn run_core_loop(
                // NetStack; the session just subscribes its topic below.
                let transport = Arc::new(IrohTransport::new(endpoint.clone()));
                net.audio_router.bind(&transport);
+                net.file_router.bind(&transport);

                let room_state = Arc::new(IrohGossipState::new(
                    endpoint.clone(),
@@ -1081,6 +1240,7 @@ async fn run_core_loop(
                    crate::log_msg(&format!("Error room_state.join failed: {:?}", e));
                    let _ = ui_tx.send(UiEvent::Error(format!("Failed to join room: {}", e))).await;
                    net.audio_router.clear();
+                    net.file_router.clear();
                    continue;
                }
                crate::log_msg("Joined room successfully via room_state");
@@ -1095,7 +1255,9 @@ async fn run_core_loop(
                // The guard unloads the module on drop — including the early-return
                // paths below, since it's a local until moved into the session. On
                // any failure, warn and fall back to the direct devices.
+                #[cfg(target_os = "linux")]
                let mut echo_cancel_guard = None;
+                #[cfg(target_os = "linux")]
                let (capture_target, playback_target) = if echo_cancellation {
                    match crate::audio::echo_cancel::enable(
                        input_device.as_deref(),
@@ -1122,11 +1284,16 @@ async fn run_core_loop(
                } else {
                    (input_device.clone(), output_device.clone())
                };
+                #[cfg(not(target_os = "linux"))]
+                let _ = echo_cancellation;
+                #[cfg(not(target_os = "linux"))]
+                let (capture_target, playback_target) = (input_device.clone(), output_device.clone());

                if let Err(e) = audio_backend.start_capture(capture_tx, capture_target) {
                    let _ = ui_tx.send(UiEvent::Error(format!("Failed to start capture: {}", e))).await;
                    let _ = room_state.leave().await;
                    net.audio_router.clear();
+                    net.file_router.clear();
                    continue;
                }

@@ -1139,6 +1306,7 @@ async fn run_core_loop(
                    let _ = audio_backend.stop();
                    let _ = room_state.leave().await;
                    net.audio_router.clear();
+                    net.file_router.clear();
                    continue;
                }

@@ -1281,6 +1449,7 @@ async fn run_core_loop(
                let peer_volumes_mixer = peer_volumes.clone();
                let peer_eq_mixer = peer_eq.clone();
                let peer_pan_mixer = peer_pan.clone();
+                let peer_gate_mixer = peer_gate.clone();
                let locally_muted_mixer = locally_muted.clone();
                let output_gain_mixer = output_gain.clone();
                let ui_tx_mixer = ui_tx.clone();
@@ -1297,6 +1466,11 @@ async fn run_core_loop(
                    // Per-peer EQ filter state. Settings are live-cloned each
                    // cycle; state is rebuilt only when a peer's EQ changes.
                    let mut peer_eqs: HashMap<EndpointId, Eq> = HashMap::new();
+                    // Per-peer noise-gate envelope state. The threshold is passed
+                    // per frame (live slider), so the gate is never rebuilt — only
+                    // created once per peer and dropped when the peer leaves.
+                    let mut peer_noise_gates: HashMap<EndpointId, crate::audio::gate::NoiseGate> =
+                        HashMap::new();
                    // When the ring is at/above target we have nothing to do; nap
                    // briefly and re-check. Short enough (relative to the ~60ms
                    // target and ~21ms device quantum) that we always refill well
@@ -1322,6 +1496,7 @@ async fn run_core_loop(
                        let current_volumes = peer_volumes_mixer.lock().await.clone();
                        let current_eq = peer_eq_mixer.lock().await.clone();
                        let current_pans = peer_pan_mixer.lock().await.clone();
+                        let current_gates = peer_gate_mixer.lock().await.clone();
                        let muted_peers = locally_muted_mixer.lock().await.clone();
                        let mut peer_frames: Vec<(Vec<i16>, f32)> = Vec::new();
                        let mut peers_seen = HashSet::new();
@@ -1347,6 +1522,26 @@ async fn run_core_loop(
                                    stems.push((peer_id, frame.clone()));
                                }

+                                // Listener-side per-peer noise gate, applied to the
+                                // raw decoded frame (after the clean stem tap, before
+                                // volume/EQ) so the threshold tracks the peer's true
+                                // signal level regardless of our volume setting. The
+                                // gate's "should transmit" return is irrelevant here —
+                                // we only attenuate. Threshold 0 = off; the gate is
+                                // created lazily and dropped when disabled.
+                                let gate_threshold =
+                                    current_gates.get(&peer_id).copied().unwrap_or(0.0);
+                                if gate_threshold > 0.0 {
+                                    peer_noise_gates
+                                        .entry(peer_id)
+                                        .or_insert_with(|| {
+                                            crate::audio::gate::NoiseGate::new(48_000)
+                                        })
+                                        .process(&mut frame, gate_threshold);
+                                } else {
+                                    peer_noise_gates.remove(&peer_id);
+                                }
+
                                let vol = current_volumes.get(&peer_id).copied().unwrap_or(1.0);
                                apply_volume(&mut frame, vol);

@@ -1391,6 +1586,8 @@ async fn run_core_loop(
                            }
                        }
                        peer_eqs.retain(|id, _| peers_seen.contains(id) || current_eq.contains_key(id));
+                        peer_noise_gates
+                            .retain(|id, _| peers_seen.contains(id) || current_gates.contains_key(id));

                        // Lossless i32 sum, then the limiter applies the master
                        // output gain (in f32, so a boost past the ceiling is
@@ -1466,6 +1663,15 @@ async fn run_core_loop(
                // The ticket of the room this event loop serves, so peer add/remove
                // updates the right per-ticket bucket in `known_peers` (A8 archive).
                let ticket_events = ticket_str.clone();
+                let (recovery_coordinator, recovery_task) =
+                    RecoveryCoordinator::spawn(room_state.clone());
+                let recovery_context = RecoveryContext {
+                    coordinator: recovery_coordinator,
+                    room_state: room_state.clone(),
+                    known_peers: known_peers.clone(),
+                    ticket: ticket_str.clone(),
+                };
+                let recovery_events = recovery_context.clone();
                // Friends store + ui sender, so a connected peer who is a friend has
                // their saved address auto-healed (W7) — populates `last_addr` so the
                // presence scheduler can reach them later.
@@ -1478,6 +1684,7 @@ async fn run_core_loop(
                                // A (re)join means the peer is back — cancel any
                                // pending reconnect grace timer before re-adding it.
                                cancel_grace_timer(&grace_timers_events, &peer_id);
+                                recovery_events.cancel(peer_id);
                                transport_events.admit_audio_sender(peer_id);
                                // Establish the audio connection as soon as the peer
                                // is known (the transport dedupes the full-mesh race).
@@ -1521,15 +1728,9 @@ async fn run_core_loop(
                                // Graceful leave — evict immediately.
                                cancel_grace_timer(&grace_timers_events, &peer_id);
                                seen_connected_events.lock().unwrap().remove(&peer_id);
-                                // Graceful leave: drop them as a rejoin dial target
-                                // for this room (a transient PeerConnectionLost
-                                // deliberately does NOT, so we can still re-dial a
-                                // peer who's still up).
-                                if let Some(peers) =
-                                    known_peers_events.lock().unwrap().get_mut(&ticket_events)
-                                {
-                                    peers.remove(&peer_id);
-                                }
+                                // A signed Leave cancels background recovery and
+                                // drops the retained target. Transient loss keeps it.
+                                recovery_events.forget(peer_id);
                                transport_events.remove_audio_sender(peer_id);
                                transport_events.disconnect_peer(peer_id).await;
                                jitter_events.lock().await.remove(&peer_id);
@@ -1543,6 +1744,7 @@ async fn run_core_loop(
                                // it. Idempotent: an ordinary mute/unmute update just
                                // re-records the same address.
                                cancel_grace_timer(&grace_timers_events, &peer_id);
+                                recovery_events.cancel(peer_id);
                                transport_events.admit_audio_sender(peer_id);
                                transport_events.connect_peer(state.addr.clone()).await;
                                // Auto-heal a friend's saved address (W7) on the
@@ -1570,11 +1772,27 @@ async fn run_core_loop(
                                    .insert(peer_id, state.addr.clone());
                                let _ = ui_tx_events.send(UiEvent::PeerUpdated { id: peer_id, state }).await;
                            }
-                            RoomEvent::ChatMessage { from, name, text, .. } => {
+                            RoomEvent::ChatMessage { from, name, text, ts: _, attachment } => {
+                                // Auto-fetch image attachments so they render inline
+                                // without a click; non-image files wait for an explicit
+                                // FetchAttachment (the "Save" chip). The descriptor was
+                                // already filename-sanitized + size-capped on ingest.
+                                if let Some(att) = attachment.clone()
+                                    && att.kind == crate::files::AttachmentKind::Image
+                                {
+                                    spawn_attachment_fetch(
+                                        transport_events.clone(),
+                                        ui_tx_events.clone(),
+                                        from,
+                                        att,
+                                        true,
+                                    );
+                                }
                                let _ = ui_tx_events.send(UiEvent::ChatMessage {
                                    from: from.to_string(),
                                    name,
                                    text,
+                                    attachment,
                                }).await;
                            }
                            RoomEvent::PeerConnectionLost(peer_id) => {
@@ -1590,9 +1808,12 @@ async fn run_core_loop(
                                arm_grace_timer(
                                    &grace_timers_events,
                                    &seen_connected_events,
-                                    &transport_events,
-                                    &jitter_events,
-                                    &ui_tx_events,
+                                    GraceExpiry {
+                                        transport: &transport_events,
+                                        jitter: &jitter_events,
+                                        ui_tx: &ui_tx_events,
+                                        recovery: Some(&recovery_events),
+                                    },
                                    RECONNECT_GRACE,
                                    peer_id,
                                );
@@ -1616,7 +1837,8 @@ async fn run_core_loop(
                    seen_connected.clone(),
                    transport.clone(),
                    jitter.clone(),
-                );
+                )
+                .with_recovery(recovery_context);
                let conn_event_task = tokio::spawn(async move {
                    while let Some(event) = conn_events.recv().await {
                        conn_handler.handle(event).await;
@@ -1630,8 +1852,10 @@ async fn run_core_loop(
                    mixer_task,
                    event_task,
                    conn_event_task,
+                    recovery_task,
                    grace_timers,
                    transport: transport.clone(),
+                    #[cfg(target_os = "linux")]
                    echo_cancel: echo_cancel_guard,
                    screenshare_host: None,
                    screenshare_viewers: Vec::new(),
@@ -1671,6 +1895,7 @@ async fn run_core_loop(
                    session.shutdown(audio_backend.clone()).await;
                    // Stop routing inbound audio links — the endpoint/router stay up.
                    net.audio_router.clear();
+                    net.file_router.clear();
                    // No longer in a gathering — friends who ping see us as just online.
                    *current_room.lock().unwrap() = None;
                    let _ = ui_tx.send(UiEvent::RoomLeft).await;
@@ -1757,6 +1982,16 @@ async fn run_core_loop(
                }
            }

+            CoreCommand::SetPeerGate(peer_id, threshold) => {
+                let threshold = threshold.clamp(0.0, 1.0);
+                let mut guard = peer_gate.lock().await;
+                if threshold <= 0.0 {
+                    guard.remove(&peer_id);
+                } else {
+                    guard.insert(peer_id, threshold);
+                }
+            }
+
            CoreCommand::SetPeerMuted(peer_id, muted) => {
                let mut guard = locally_muted.lock().await;
                if muted {
@@ -1807,17 +2042,26 @@ async fn run_core_loop(
            }

            CoreCommand::SetNetworkMode(mode) => {
-                network_mode = mode;
-                // Rebuild the persistent stack to the new posture immediately if
-                // idle; if a call is active, defer to the next Leave/Join so the
-                // live call isn't disrupted (preserves "applies on next join").
-                if active_session.is_none() {
-                    let lookup = net.memory_lookup.clone();
-                    net.shutdown().await;
-                    let publish = presence_mode.lock().unwrap().publishes_to_discovery();
-                    net = build_net_stack(secret_key.clone(), network_mode, lookup, friends_handler.clone(), publish).await?;
-                } else {
-                    net_rebuild_pending = true;
+                // Skip when the posture is unchanged. The GUI re-sends the saved
+                // network mode as part of its startup config-sync, and that mode
+                // usually already matches the freshly-built stack — rebuilding the
+                // iroh endpoint for an identical posture just churns the network
+                // and adds a needless ~1s teardown+rebuild bounce at every launch
+                // (seen on both Linux and Windows/Wine). A real change still
+                // rebuilds exactly as before.
+                if mode != network_mode {
+                    network_mode = mode;
+                    // Rebuild the persistent stack to the new posture immediately if
+                    // idle; if a call is active, defer to the next Leave/Join so the
+                    // live call isn't disrupted (preserves "applies on next join").
+                    if active_session.is_none() {
+                        let lookup = net.memory_lookup.clone();
+                        net.shutdown().await;
+                        let publish = presence_mode.lock().unwrap().publishes_to_discovery();
+                        net = build_net_stack(secret_key.clone(), network_mode, lookup, friends_handler.clone(), publish).await?;
+                    } else {
+                        net_rebuild_pending = true;
+                    }
                }
            }

@@ -2031,12 +2275,38 @@ async fn run_core_loop(

            CoreCommand::SendChat(text) => {
                if let Some(session) = &active_session
-                    && let Err(e) = session.room_state.send_chat(text).await
+                    && let Err(e) = session.room_state.send_chat(text, None).await
                {
                    crate::log_msg(&format!("Failed to send chat: {e}"));
                }
            }

+            CoreCommand::SendChatFile { text, attachment, data } => {
+                if let Some(session) = &active_session {
+                    // Make the bytes fetchable by room members, then broadcast the
+                    // descriptor alongside the (possibly empty) caption text.
+                    session
+                        .transport
+                        .serve_attachment(attachment.id, Arc::new(data));
+                    if let Err(e) = session.room_state.send_chat(text, Some(attachment)).await {
+                        crate::log_msg(&format!("Failed to send chat file: {e}"));
+                    }
+                }
+            }
+
+            CoreCommand::FetchAttachment { from, attachment } => {
+                if let Some(session) = &active_session {
+                    let is_image = attachment.kind == crate::files::AttachmentKind::Image;
+                    spawn_attachment_fetch(
+                        session.transport.clone(),
+                        ui_tx.clone(),
+                        from,
+                        attachment,
+                        is_image,
+                    );
+                }
+            }
+
            CoreCommand::SetPixelpassPath(path) => {
                pixelpass_override = path.filter(|p| !p.trim().is_empty());
            }
@@ -0,0 +1,264 @@
+use crate::network::{RoomState, gossip::IrohGossipState};
+use iroh::{EndpointAddr, EndpointId};
+use std::collections::{HashMap, HashSet};
+use std::sync::{Arc, Mutex};
+use std::time::Duration;
+use tokio::sync::mpsc;
+use tokio::task::JoinHandle;
+use tokio::time::Instant;
+
+const RECOVERY_COMMAND_CAPACITY: usize = 64;
+const RECOVERY_DELAYS: [Duration; 7] = [
+    Duration::from_secs(1),
+    Duration::from_secs(2),
+    Duration::from_secs(4),
+    Duration::from_secs(8),
+    Duration::from_secs(15),
+    Duration::from_secs(30),
+    Duration::from_secs(60),
+];
+
+fn recovery_delay(attempt: usize) -> Duration {
+    RECOVERY_DELAYS[attempt.min(RECOVERY_DELAYS.len() - 1)]
+}
+
+enum RecoveryCommand {
+    Start {
+        peer_id: EndpointId,
+        addr: EndpointAddr,
+    },
+    Cancel(EndpointId),
+}
+
+struct RecoveryEntry {
+    addr: EndpointAddr,
+    attempt: usize,
+    next_attempt: Instant,
+}
+
+#[async_trait::async_trait]
+trait RecoveryRoom: Send + Sync {
+    async fn rebootstrap_peers(&self, peers: Vec<EndpointAddr>) -> Result<(), String>;
+}
+
+#[async_trait::async_trait]
+impl RecoveryRoom for IrohGossipState {
+    async fn rebootstrap_peers(&self, peers: Vec<EndpointAddr>) -> Result<(), String> {
+        RoomState::rebootstrap_peers(self, peers)
+            .await
+            .map_err(|error| error.to_string())
+    }
+}
+
+/// Cloneable command side of the single per-session recovery coordinator.
+/// `active` is shared with transport/event handlers so cancellation is visible
+/// immediately even while the coordinator is awaiting an in-flight gossip call.
+#[derive(Clone)]
+pub(super) struct RecoveryCoordinator {
+    tx: mpsc::Sender<RecoveryCommand>,
+    active: Arc<Mutex<HashSet<EndpointId>>>,
+}
+
+impl RecoveryCoordinator {
+    pub(super) fn spawn(room_state: Arc<IrohGossipState>) -> (Self, JoinHandle<()>) {
+        Self::spawn_inner(room_state)
+    }
+
+    fn spawn_inner(room_state: Arc<dyn RecoveryRoom>) -> (Self, JoinHandle<()>) {
+        let (tx, rx) = mpsc::channel(RECOVERY_COMMAND_CAPACITY);
+        let active = Arc::new(Mutex::new(HashSet::new()));
+        let handle = Self {
+            tx,
+            active: active.clone(),
+        };
+        let task = tokio::spawn(run_coordinator(room_state, active, rx));
+        (handle, task)
+    }
+
+    /// Reserve one recovery slot before grace-expiry teardown begins. Returns
+    /// false when the peer is already recovering, preventing duplicate work.
+    pub(super) fn begin(&self, peer_id: EndpointId) -> bool {
+        self.active.lock().unwrap().insert(peer_id)
+    }
+
+    /// Activate the reserved slot with its retained authenticated address.
+    /// Uses a bounded non-blocking send while holding the active-set lock so a
+    /// concurrent cancellation is ordered before or after this command.
+    pub(super) fn activate(&self, peer_id: EndpointId, addr: EndpointAddr) -> Result<bool, ()> {
+        let mut active = self.active.lock().unwrap();
+        if !active.contains(&peer_id) {
+            return Ok(false);
+        }
+        if self
+            .tx
+            .try_send(RecoveryCommand::Start { peer_id, addr })
+            .is_err()
+        {
+            active.remove(&peer_id);
+            return Err(());
+        }
+        Ok(true)
+    }
+
+    pub(super) fn cancel(&self, peer_id: EndpointId) {
+        self.active.lock().unwrap().remove(&peer_id);
+        // Cancellation is governed by the shared active set, so it remains
+        // immediate even if the bounded command queue is temporarily full.
+        let _ = self.tx.try_send(RecoveryCommand::Cancel(peer_id));
+    }
+
+    pub(super) fn is_active(&self, peer_id: &EndpointId) -> bool {
+        self.active.lock().unwrap().contains(peer_id)
+    }
+}
+
+async fn run_coordinator(
+    room_state: Arc<dyn RecoveryRoom>,
+    active: Arc<Mutex<HashSet<EndpointId>>>,
+    mut rx: mpsc::Receiver<RecoveryCommand>,
+) {
+    let mut entries: HashMap<EndpointId, RecoveryEntry> = HashMap::new();
+
+    loop {
+        // The shared active set is the authoritative cancellation gate. Prune
+        // here as well as on Cancel commands so a saturated command queue cannot
+        // leave an inactive, past-due entry spinning the timer loop.
+        let active_snapshot = active.lock().unwrap().clone();
+        entries.retain(|peer_id, _| active_snapshot.contains(peer_id));
+        let next_deadline = entries.values().map(|entry| entry.next_attempt).min();
+        let command = match next_deadline {
+            Some(deadline) => {
+                tokio::select! {
+                    command = rx.recv() => command,
+                    _ = tokio::time::sleep_until(deadline) => {
+                        let now = Instant::now();
+                        let active_snapshot = active.lock().unwrap().clone();
+                        let due: Vec<(EndpointId, EndpointAddr)> = entries
+                            .iter()
+                            .filter(|(id, entry)| {
+                                entry.next_attempt <= now && active_snapshot.contains(*id)
+                            })
+                            .map(|(id, entry)| (*id, entry.addr.clone()))
+                            .collect();
+
+                        if !due.is_empty() {
+                            let addrs = due.iter().map(|(_, addr)| addr.clone()).collect();
+                            if let Err(error) = room_state.rebootstrap_peers(addrs).await {
+                                crate::log_msg(&format!(
+                                    "Background peer recovery attempt failed: {error}"
+                                ));
+                            }
+
+                            let scheduled_at = Instant::now();
+                            for (peer_id, _) in due {
+                                if !active.lock().unwrap().contains(&peer_id) {
+                                    entries.remove(&peer_id);
+                                    continue;
+                                }
+                                if let Some(entry) = entries.get_mut(&peer_id) {
+                                    entry.next_attempt = scheduled_at + recovery_delay(entry.attempt);
+                                    entry.attempt = entry.attempt.saturating_add(1);
+                                }
+                            }
+                        }
+                        continue;
+                    }
+                }
+            }
+            None => rx.recv().await,
+        };
+
+        match command {
+            Some(RecoveryCommand::Start { peer_id, addr }) => {
+                if active.lock().unwrap().contains(&peer_id) {
+                    entries.entry(peer_id).or_insert(RecoveryEntry {
+                        addr,
+                        attempt: 0,
+                        next_attempt: Instant::now(),
+                    });
+                }
+            }
+            Some(RecoveryCommand::Cancel(peer_id)) => {
+                entries.remove(&peer_id);
+            }
+            None => break,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use iroh::SecretKey;
+
+    struct RecordingRoom {
+        attempts: mpsc::UnboundedSender<Vec<EndpointAddr>>,
+    }
+
+    #[async_trait::async_trait]
+    impl RecoveryRoom for RecordingRoom {
+        async fn rebootstrap_peers(&self, peers: Vec<EndpointAddr>) -> Result<(), String> {
+            self.attempts.send(peers).map_err(|error| error.to_string())
+        }
+    }
+
+    #[test]
+    fn retry_backoff_reaches_and_stays_at_sixty_seconds() {
+        let actual: Vec<u64> = (0..10)
+            .map(|attempt| recovery_delay(attempt).as_secs())
+            .collect();
+        assert_eq!(actual, vec![1, 2, 4, 8, 15, 30, 60, 60, 60, 60]);
+    }
+
+    #[test]
+    fn recovery_slots_are_deduplicated_and_cancel_immediately() {
+        let (tx, mut rx) = mpsc::channel(4);
+        let coordinator = RecoveryCoordinator {
+            tx,
+            active: Arc::new(Mutex::new(HashSet::new())),
+        };
+        let peer_id = SecretKey::generate().public();
+
+        assert!(coordinator.begin(peer_id));
+        assert!(
+            !coordinator.begin(peer_id),
+            "a peer gets only one recovery slot"
+        );
+        assert_eq!(
+            coordinator.activate(peer_id, EndpointAddr::from(peer_id)),
+            Ok(true)
+        );
+        assert!(matches!(
+            rx.try_recv(),
+            Ok(RecoveryCommand::Start { peer_id: id, .. }) if id == peer_id
+        ));
+
+        coordinator.cancel(peer_id);
+        assert!(!coordinator.is_active(&peer_id));
+        assert!(matches!(
+            rx.try_recv(),
+            Ok(RecoveryCommand::Cancel(id)) if id == peer_id
+        ));
+    }
+
+    #[tokio::test]
+    async fn coordinator_attempts_rebootstrap_immediately() {
+        let (attempts_tx, mut attempts_rx) = mpsc::unbounded_channel();
+        let (coordinator, task) = RecoveryCoordinator::spawn_inner(Arc::new(RecordingRoom {
+            attempts: attempts_tx,
+        }));
+        let peer_id = SecretKey::generate().public();
+        let addr = EndpointAddr::from(peer_id);
+
+        assert!(coordinator.begin(peer_id));
+        assert_eq!(coordinator.activate(peer_id, addr.clone()), Ok(true));
+        let attempted = tokio::time::timeout(Duration::from_secs(1), attempts_rx.recv())
+            .await
+            .expect("first recovery attempt should be immediate")
+            .expect("recording room remains subscribed");
+        assert_eq!(attempted, vec![addr]);
+
+        coordinator.cancel(peer_id);
+        task.abort();
+    }
+}
@@ -0,0 +1,295 @@
+//! Chat file attachments: the compact descriptor that rides a gossip chat
+//! message, plus the pure validation/sanitization seams for the file-transfer
+//! plane.
+//!
+//! Attachment **bytes do not travel over gossip** — gossip is a small-frame
+//! broadcast plane (see `avatar` for why image bytes there are hard-capped to
+//! tens of KB). Instead a chat message carries a [`ChatAttachment`] *descriptor*
+//! (name, size, kind, id); the sender serves the actual bytes over the dedicated
+//! file ALPN (`protocol::FILES_ALPN`) via direct QUIC streams, and recipients
+//! fetch them point-to-point. Everything in this module is dependency-light and
+//! pure so it can be unit-tested away from the network and the GUI.
+
+use serde::{Deserialize, Serialize};
+
+/// Hard ceiling on a single attachment's byte size. Bounds the memory a peer can
+/// make us hold (when fetching) or serve, and the time a transfer can take.
+/// 25 MiB comfortably covers phone photos and ordinary documents.
+pub const MAX_ATTACHMENT_BYTES: u64 = 25 * 1024 * 1024;
+
+/// Max decoded pixels per side for an inline image preview. Defends against a
+/// decode-bomb (a small file that expands to an enormous bitmap), independent of
+/// the byte cap. Applied via `image::Limits` when validating/decoding.
+pub const MAX_IMAGE_PX: u32 = 4096;
+
+/// Longest filename we keep and display. Keeps the gossip descriptor compact and
+/// the UI tidy; the real bytes are unaffected.
+pub const MAX_FILENAME_LEN: usize = 96;
+
+/// A 32-byte opaque id identifying one attachment for the fetch request. Minted
+/// randomly per attachment by the sender (see core); the transfer itself is
+/// authenticated + encrypted + room-member gated, so the id only needs to be a
+/// hard-to-guess handle into the sender's serve store, not a content hash.
+pub type AttachmentId = [u8; 32];
+
+/// How the receiver should present an attachment. A *hint* derived from the
+/// sender's content sniff — never trusted for a safety decision. The receiver
+/// re-validates image bytes itself before decoding, and falls back to a file
+/// chip if an "Image" doesn't actually decode.
+#[derive(Serialize, Deserialize, Clone, Copy, PartialEq, Eq, Debug)]
+pub enum AttachmentKind {
+    Image,
+    File,
+}
+
+/// The descriptor carried inside a `GossipMessage::Chat`. Compact by design: it
+/// holds no file bytes, only what the UI needs to render a placeholder/chip and
+/// what a fetch needs to pull the bytes.
+#[derive(Serialize, Deserialize, Clone, PartialEq, Eq, Debug)]
+pub struct ChatAttachment {
+    /// Sanitized display filename (already path-stripped — see
+    /// [`sanitize_filename`]). Never used as a filesystem path on receipt without
+    /// the user choosing a save location.
+    pub name: String,
+    /// Byte length of the file. Bounds the fetch read; must be
+    /// `<= MAX_ATTACHMENT_BYTES` (enforced by [`size_within_cap`]).
+    pub size: u64,
+    /// Presentation hint (image vs. generic file).
+    pub kind: AttachmentKind,
+    /// Opaque handle the receiver writes on the file plane to request the bytes.
+    pub id: AttachmentId,
+}
+
+/// Sanitize an arbitrary (possibly hostile) filename for display and as a
+/// save-dialog default. Strips any directory component (both `/` and `\`),
+/// removes control characters, collapses whitespace, trims, caps the length
+/// while trying to preserve a short extension, and rejects the `.`/`..` traps.
+/// Always returns a non-empty, path-component-free name (falls back to `file`).
+pub fn sanitize_filename(raw: &str) -> String {
+    // Take only the final *non-empty* path component, defeating
+    // `../../etc/passwd`, `C:\foo\bar`, embedded separators, and trailing slashes
+    // (`a/b/c/` → `c`).
+    let base = raw
+        .rsplit(['/', '\\'])
+        .find(|s| !s.trim().is_empty())
+        .unwrap_or("")
+        .trim();
+
+    // Drop control chars; turn other whitespace into single spaces later.
+    let cleaned: String = base
+        .chars()
+        .filter(|c| !c.is_control())
+        .collect();
+    let collapsed = cleaned.split_whitespace().collect::<Vec<_>>().join(" ");
+    let collapsed = collapsed.trim_matches('.').trim();
+
+    if collapsed.is_empty() {
+        return "file".to_string();
+    }
+    if collapsed.chars().count() <= MAX_FILENAME_LEN {
+        return collapsed.to_string();
+    }
+
+    // Too long: keep the extension (if short + sane) and truncate the stem.
+    if let Some((stem, ext)) = collapsed.rsplit_once('.')
+        && !ext.is_empty()
+        && ext.chars().count() <= 8
+        && ext.chars().all(|c| c.is_ascii_alphanumeric())
+    {
+        let keep = MAX_FILENAME_LEN.saturating_sub(ext.chars().count() + 1);
+        let truncated: String = stem.chars().take(keep).collect();
+        return format!("{truncated}.{ext}");
+    }
+    collapsed.chars().take(MAX_FILENAME_LEN).collect()
+}
+
+/// Whether a declared/observed size is within the transfer cap and non-zero.
+/// Used both when sending (reject before serving) and when fetching (reject a
+/// descriptor before opening a stream).
+pub fn size_within_cap(size: u64) -> bool {
+    size > 0 && size <= MAX_ATTACHMENT_BYTES
+}
+
+/// Sniff the leading bytes for a known image container, to set the attachment
+/// *kind* hint at send time. Recognizes PNG, JPEG, GIF, WebP, and BMP. This is a
+/// presentation hint only — actual inline rendering still depends on the bytes
+/// decoding (we only build image features for PNG/JPEG), with a file-chip
+/// fallback otherwise.
+pub fn is_probably_image(bytes: &[u8]) -> bool {
+    let b = bytes;
+    let png = b.starts_with(&[0x89, b'P', b'N', b'G', 0x0D, 0x0A, 0x1A, 0x0A]);
+    let jpeg = b.starts_with(&[0xFF, 0xD8, 0xFF]);
+    let gif = b.starts_with(b"GIF87a") || b.starts_with(b"GIF89a");
+    let bmp = b.starts_with(b"BM");
+    let webp = b.len() >= 12 && b.starts_with(b"RIFF") && &b[8..12] == b"WEBP";
+    png || jpeg || gif || bmp || webp
+}
+
+/// The attachment kind for some file bytes: [`AttachmentKind::Image`] if it
+/// sniffs as an image container, else [`AttachmentKind::File`].
+pub fn classify(bytes: &[u8]) -> AttachmentKind {
+    if is_probably_image(bytes) {
+        AttachmentKind::Image
+    } else {
+        AttachmentKind::File
+    }
+}
+
+/// Defensively decode image bytes under strict pixel limits to confirm they're a
+/// real, sane image before we hand them to the renderer. Returns the decoded
+/// dimensions on success. Guards against decode-bombs (small file → huge bitmap)
+/// regardless of [`MAX_ATTACHMENT_BYTES`]. Only PNG/JPEG are buildable in our
+/// `image` feature set; anything else returns `None` and the caller shows a chip.
+pub fn validate_image_bytes(bytes: &[u8]) -> Option<(u32, u32)> {
+    let mut limits = image::Limits::default();
+    limits.max_image_width = Some(MAX_IMAGE_PX);
+    limits.max_image_height = Some(MAX_IMAGE_PX);
+    let reader = image::ImageReader::new(std::io::Cursor::new(bytes))
+        .with_guessed_format()
+        .ok()?;
+    let mut reader = reader;
+    reader.limits(limits);
+    let img = reader.decode().ok()?;
+    let (w, h) = (img.width(), img.height());
+    if w == 0 || h == 0 || w > MAX_IMAGE_PX || h > MAX_IMAGE_PX {
+        return None;
+    }
+    Some((w, h))
+}
+
+/// Parse a file-plane request: it must be exactly one [`AttachmentId`] (32
+/// bytes). Anything else is rejected so a peer can't send a malformed/oversized
+/// request frame. Pure half of the serve handler.
+pub fn parse_request(bytes: &[u8]) -> Option<AttachmentId> {
+    if bytes.len() != 32 {
+        return None;
+    }
+    let mut id = [0u8; 32];
+    id.copy_from_slice(bytes);
+    Some(id)
+}
+
+/// A human-readable size like `2.3 MB` / `812 KB` / `40 B` for the file chip.
+pub fn human_size(bytes: u64) -> String {
+    const KB: u64 = 1024;
+    const MB: u64 = 1024 * KB;
+    if bytes >= MB {
+        format!("{:.1} MB", bytes as f64 / MB as f64)
+    } else if bytes >= KB {
+        format!("{:.0} KB", bytes as f64 / KB as f64)
+    } else {
+        format!("{bytes} B")
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn sanitize_strips_directory_traversal() {
+        assert_eq!(sanitize_filename("../../etc/passwd"), "passwd");
+        assert_eq!(sanitize_filename("/abs/path/photo.png"), "photo.png");
+        assert_eq!(sanitize_filename(r"C:\Users\me\secret.doc"), "secret.doc");
+        assert_eq!(sanitize_filename("a/b/c/"), "c");
+    }
+
+    #[test]
+    fn sanitize_rejects_dot_traps_and_empty() {
+        assert_eq!(sanitize_filename(""), "file");
+        assert_eq!(sanitize_filename("."), "file");
+        assert_eq!(sanitize_filename(".."), "file");
+        assert_eq!(sanitize_filename("   "), "file");
+        assert_eq!(sanitize_filename("/"), "file");
+    }
+
+    #[test]
+    fn sanitize_removes_control_chars_and_collapses_ws() {
+        // Control chars (incl. tab/newline) are stripped entirely.
+        assert_eq!(sanitize_filename("my\tphoto\n.png"), "myphoto.png");
+        assert_eq!(sanitize_filename("a\u{0000}b.txt"), "ab.txt");
+        // Real spaces are collapsed but preserved.
+        assert_eq!(sanitize_filename("my  photo .png"), "my photo .png");
+    }
+
+    #[test]
+    fn sanitize_caps_length_preserving_extension() {
+        let long_stem = "x".repeat(200);
+        let name = format!("{long_stem}.png");
+        let out = sanitize_filename(&name);
+        assert!(out.chars().count() <= MAX_FILENAME_LEN, "len was {}", out.chars().count());
+        assert!(out.ends_with(".png"), "extension preserved: {out}");
+    }
+
+    #[test]
+    fn size_cap_bounds() {
+        assert!(!size_within_cap(0));
+        assert!(size_within_cap(1));
+        assert!(size_within_cap(MAX_ATTACHMENT_BYTES));
+        assert!(!size_within_cap(MAX_ATTACHMENT_BYTES + 1));
+    }
+
+    #[test]
+    fn image_sniffing_recognizes_containers() {
+        assert!(is_probably_image(&[0x89, b'P', b'N', b'G', 0x0D, 0x0A, 0x1A, 0x0A, 0, 0]));
+        assert!(is_probably_image(&[0xFF, 0xD8, 0xFF, 0xE0]));
+        assert!(is_probably_image(b"GIF89a...."));
+        let mut webp = b"RIFF".to_vec();
+        webp.extend_from_slice(&[0, 0, 0, 0]);
+        webp.extend_from_slice(b"WEBP");
+        assert!(is_probably_image(&webp));
+        assert!(!is_probably_image(b"%PDF-1.7"));
+        assert!(!is_probably_image(b""));
+    }
+
+    #[test]
+    fn classify_maps_sniff_to_kind() {
+        assert_eq!(classify(&[0xFF, 0xD8, 0xFF]), AttachmentKind::Image);
+        assert_eq!(classify(b"plain text"), AttachmentKind::File);
+    }
+
+    #[test]
+    fn parse_request_requires_exact_32_bytes() {
+        assert_eq!(parse_request(&[7u8; 32]), Some([7u8; 32]));
+        assert_eq!(parse_request(&[7u8; 31]), None);
+        assert_eq!(parse_request(&[7u8; 33]), None);
+        assert_eq!(parse_request(&[]), None);
+    }
+
+    #[test]
+    fn validate_image_rejects_garbage() {
+        assert_eq!(validate_image_bytes(b"not an image"), None);
+        assert_eq!(validate_image_bytes(&[]), None);
+    }
+
+    #[test]
+    fn validate_image_accepts_a_real_png() {
+        // Encode a tiny PNG in-memory, then validate it.
+        let img = image::RgbImage::from_pixel(4, 3, image::Rgb([10, 20, 30]));
+        let mut buf = std::io::Cursor::new(Vec::new());
+        image::DynamicImage::ImageRgb8(img)
+            .write_to(&mut buf, image::ImageFormat::Png)
+            .unwrap();
+        assert_eq!(validate_image_bytes(&buf.into_inner()), Some((4, 3)));
+    }
+
+    #[test]
+    fn human_size_units() {
+        assert_eq!(human_size(40), "40 B");
+        assert_eq!(human_size(2048), "2 KB");
+        assert_eq!(human_size(3 * 1024 * 1024 + 300 * 1024), "3.3 MB");
+    }
+
+    #[test]
+    fn attachment_descriptor_round_trips_json() {
+        let a = ChatAttachment {
+            name: "photo.png".to_string(),
+            size: 12345,
+            kind: AttachmentKind::Image,
+            id: [9u8; 32],
+        };
+        let bytes = serde_json::to_vec(&a).unwrap();
+        let back: ChatAttachment = serde_json::from_slice(&bytes).unwrap();
+        assert_eq!(a, back);
+    }
+}
@@ -15,15 +15,20 @@ pub mod notify;
 pub mod screenshare;
 pub mod sanitize;
 pub mod avatar;
+pub mod background;
 pub mod recents;
 pub mod discovery;
 pub mod hotkeys;
+pub mod files;

 use std::fs::File;
 use std::path::{Path, PathBuf};
 use std::sync::OnceLock;

 const LOG_MAX_BYTES: u64 = 5 * 1024 * 1024;
+// Owner-only log permissions are a Unix concept (mode bits); on Windows the log
+// inherits the directory's default ACL. Only referenced under `cfg(unix)`.
+#[cfg(unix)]
 const LOG_MODE: u32 = 0o600;

 /// Resolves the log file path once: `$XDG_STATE_HOME/peerspeak/peerspeak.log`
@@ -84,8 +89,6 @@ fn prepare_log_file(path: &Path) -> std::io::Result<File> {
 }

 fn prepare_log_file_with_limit(path: &Path, max_bytes: u64) -> std::io::Result<File> {
-    use std::os::unix::fs::{OpenOptionsExt, PermissionsExt};
-
    if let Some(parent) = path.parent() {
        let _ = std::fs::create_dir_all(parent);
    }
@@ -98,12 +101,23 @@ fn prepare_log_file_with_limit(path: &Path, max_bytes: u64) -> std::io::Result<F
        }
    }

-    let file = std::fs::OpenOptions::new()
-        .create(true)
-        .append(true)
-        .mode(LOG_MODE)
-        .open(path)?;
-    let _ = std::fs::set_permissions(path, std::fs::Permissions::from_mode(LOG_MODE));
+    let mut opts = std::fs::OpenOptions::new();
+    opts.create(true).append(true);
+    // The log can carry capability-bearing values (redacted, but still): keep it
+    // owner-only on Unix via the open mode. Windows has no mode bits; it inherits
+    // the directory ACL, so this hardening is Unix-only.
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::OpenOptionsExt;
+        opts.mode(LOG_MODE);
+    }
+    let file = opts.open(path)?;
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        // Re-assert the mode in case the file pre-existed with looser perms.
+        let _ = std::fs::set_permissions(path, std::fs::Permissions::from_mode(LOG_MODE));
+    }
    Ok(file)
 }

@@ -126,6 +140,7 @@ pub fn log_msg(msg: &str) {
 mod tests {
    use super::*;
    use std::io::Write;
+    #[cfg(unix)]
    use std::os::unix::fs::PermissionsExt;

    fn temp_log_dir() -> PathBuf {
@@ -145,6 +160,9 @@ mod tests {
        assert_eq!(redact_for_log("   "), "<redacted:empty>");
    }

+    // Owner-only log perms are a Unix concept; on Windows the file inherits the
+    // directory ACL and there's no mode to assert.
+    #[cfg(unix)]
    #[test]
    fn log_file_is_created_private() {
        let dir = temp_log_dir();
@@ -1,3 +1,7 @@
+// On Windows, suppress the extra console window for release GUI builds while
+// keeping it in debug builds so stderr/panics stay visible during development.
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
 fn main() {
    if let Err(e) = peerspeak::app::run_gui() {
        eprintln!("Error running GUI: {:?}", e);
@@ -5,7 +5,7 @@ use iroh_gossip::proto::TopicId;
 use tokio::sync::mpsc;
 use tokio::sync::mpsc::Receiver;
 use std::sync::{Arc, Mutex};
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use async_trait::async_trait;
 use tokio_stream::StreamExt;
 use serde::{Serialize, Deserialize};
@@ -184,9 +184,16 @@ fn compute_bootstrap(
 pub enum GossipMessage {
    Announce(PeerState),
    Leave,
-    /// A room text-chat message: the author's display name, the text, and a
-    /// sender-stamped millisecond timestamp.
-    Chat { name: String, text: String, ts: u64 },
+    /// A room text-chat message: the author's display name, the text, a
+    /// sender-stamped millisecond timestamp, and an optional file attachment
+    /// descriptor (the bytes are fetched off-gossip on the file plane).
+    Chat {
+        name: String,
+        text: String,
+        ts: u64,
+        #[serde(default)]
+        attachment: Option<crate::files::ChatAttachment>,
+    },
 }

 pub struct IrohGossipState {
@@ -198,6 +205,10 @@ pub struct IrohGossipState {
    secret_key: SecretKey,
    self_state: Arc<Mutex<Option<PeerState>>>,
    peers: Arc<Mutex<HashMap<EndpointId, PeerState>>>,
+    /// Previously verified peers whose live roster entry was removed by a
+    /// transient disconnect. Retained only so a later authenticated `Leave`
+    /// still reaches core and cancels background recovery.
+    disconnected_peers: Arc<Mutex<HashSet<EndpointId>>>,
    event_tx: mpsc::Sender<RoomEvent>,
    event_rx: Mutex<Option<mpsc::Receiver<RoomEvent>>>,
    active_topic: Mutex<Option<tokio::task::JoinHandle<()>>>,
@@ -223,6 +234,7 @@ impl IrohGossipState {
            secret_key,
            self_state: Arc::new(Mutex::new(None)),
            peers: Arc::new(Mutex::new(HashMap::new())),
+            disconnected_peers: Arc::new(Mutex::new(HashSet::new())),
            event_tx,
            event_rx: Mutex::new(Some(event_rx)),
            active_topic: Mutex::new(None),
@@ -295,6 +307,7 @@ impl RoomState for IrohGossipState {

        let event_tx = self.event_tx.clone();
        let peers = self.peers.clone();
+        let disconnected_peers = self.disconnected_peers.clone();
        let address_lookup = self.address_lookup.clone();
        let self_state_clone = self.self_state.clone();
        let gossip_sender_clone = gossip_sender.clone();
@@ -393,6 +406,7 @@ impl RoomState for IrohGossipState {
                                        // peer-supplied: cap/validate once at ingest
                                        // so invalid offers never render a Watch button.
                                        state.sharing = state.sharing.and_then(crate::screenshare::sanitize_ticket);
+                                        disconnected_peers.lock().unwrap().remove(&payload.author);
                                        let (is_new, state_changed) = {
                                            let mut peer_map = peers.lock().unwrap();
                                            let is_new = !peer_map.contains_key(&payload.author);
@@ -423,17 +437,32 @@ impl RoomState for IrohGossipState {
                                    GossipMessage::Leave => {
                                        crate::log_msg(&format!("Gossip peer leave request from author={:?}", payload.author));
                                        let removed = peers.lock().unwrap().remove(&payload.author).is_some();
-                                        if removed {
+                                        let was_disconnected = disconnected_peers
+                                            .lock()
+                                            .unwrap()
+                                            .remove(&payload.author);
+                                        if removed || was_disconnected {
                                            let _ = event_tx.send(RoomEvent::PeerLeft(payload.author)).await;
                                        }
                                    }
-                                    GossipMessage::Chat { name, text, ts } => {
+                                    GossipMessage::Chat { name, text, ts, attachment } => {
                                        crate::log_msg(&format!("Gossip chat from author={:?}", payload.author));
+                                        // Defensively normalize an untrusted attachment
+                                        // descriptor: sanitize the filename and drop it
+                                        // entirely if it declares an out-of-cap size.
+                                        let attachment = attachment.and_then(|mut a| {
+                                            if !crate::files::size_within_cap(a.size) {
+                                                return None;
+                                            }
+                                            a.name = crate::files::sanitize_filename(&a.name);
+                                            Some(a)
+                                        });
                                        let _ = event_tx.send(RoomEvent::ChatMessage {
                                            from: payload.author,
                                            name,
                                            text,
                                            ts,
+                                            attachment,
                                        }).await;
                                    }
                                }
@@ -472,6 +501,7 @@ impl RoomState for IrohGossipState {
                        // cached presence entry; a rejoin re-announces as new.
                        let removed = peers.lock().unwrap().remove(&peer_id).is_some();
                        if removed {
+                            disconnected_peers.lock().unwrap().insert(peer_id);
                            crate::log_msg(&format!("Peer connection lost (NeighborDown): {:?}", peer_id));
                            let _ = event_tx.send(RoomEvent::PeerConnectionLost(peer_id)).await;
                        }
@@ -516,7 +546,48 @@ impl RoomState for IrohGossipState {
        Ok(())
    }

-    async fn send_chat(&self, text: String) -> Result<(), NetError> {
+    async fn rebootstrap_peers(&self, peers: Vec<EndpointAddr>) -> Result<(), NetError> {
+        let self_id = self._endpoint.id();
+        let mut peer_ids = Vec::new();
+        for addr in peers {
+            if addr.id == self_id || peer_ids.contains(&addr.id) {
+                continue;
+            }
+            self.address_lookup.add_endpoint_info(addr.clone());
+            peer_ids.push(addr.id);
+        }
+
+        if peer_ids.is_empty() {
+            return Ok(());
+        }
+
+        // Clone the sender before awaiting: active_sender is a standard mutex and
+        // must never be held across an async gossip operation.
+        let sender = self
+            .active_sender
+            .lock()
+            .unwrap()
+            .clone()
+            .ok_or_else(|| NetError::Other("Not in a room".to_string()))?;
+
+        crate::log_msg(&format!("Rebootstrapping gossip peers: {:?}", peer_ids));
+        sender
+            .join_peers(peer_ids)
+            .await
+            .map_err(|e| NetError::Gossip(e.to_string()))
+    }
+
+    fn mark_peer_disconnected(&self, peer_id: EndpointId) {
+        if self.peers.lock().unwrap().remove(&peer_id).is_some() {
+            self.disconnected_peers.lock().unwrap().insert(peer_id);
+        }
+    }
+
+    async fn send_chat(
+        &self,
+        text: String,
+        attachment: Option<crate::files::ChatAttachment>,
+    ) -> Result<(), NetError> {
        let name = {
            let guard = self.self_state.lock().unwrap();
            match guard.as_ref() {
@@ -533,7 +604,7 @@ impl RoomState for IrohGossipState {
                &self.secret_key,
                &topic,
                ts,
-                GossipMessage::Chat { name, text, ts },
+                GossipMessage::Chat { name, text, ts, attachment },
            );
            if let Ok(bytes) = serde_json::to_vec(&payload) {
                sender.broadcast(bytes.into()).await
@@ -571,6 +642,7 @@ impl RoomState for IrohGossipState {
        }

        self.peers.lock().unwrap().clear();
+        self.disconnected_peers.lock().unwrap().clear();
        Ok(())
    }

@@ -694,13 +766,15 @@ mod tests {
            name: "Alice".to_string(),
            text: "Hello".to_string(),
            ts: 123456789,
+            attachment: None,
        };
        let serialized = serde_json::to_string(&original).unwrap();
        let deserialized: GossipMessage = serde_json::from_str(&serialized).unwrap();
-        if let GossipMessage::Chat { name, text, ts } = deserialized {
+        if let GossipMessage::Chat { name, text, ts, attachment } = deserialized {
            assert_eq!(name, "Alice");
            assert_eq!(text, "Hello");
            assert_eq!(ts, 123456789);
+            assert_eq!(attachment, None);
        } else {
            panic!("Expected GossipMessage::Chat");
        }
@@ -710,10 +784,11 @@ mod tests {
            name: "".to_string(),
            text: "".to_string(),
            ts: u64::MAX,
+            attachment: None,
        };
        let serialized_empty = serde_json::to_string(&original_empty).unwrap();
        let deserialized_empty: GossipMessage = serde_json::from_str(&serialized_empty).unwrap();
-        if let GossipMessage::Chat { name, text, ts } = deserialized_empty {
+        if let GossipMessage::Chat { name, text, ts, .. } = deserialized_empty {
            assert_eq!(name, "");
            assert_eq!(text, "");
            assert_eq!(ts, u64::MAX);
@@ -722,6 +797,40 @@ mod tests {
        }
    }

+    #[test]
+    fn test_gossip_chat_attachment_round_trip_and_back_compat() {
+        let att = crate::files::ChatAttachment {
+            name: "photo.png".to_string(),
+            size: 4096,
+            kind: crate::files::AttachmentKind::Image,
+            id: [42u8; 32],
+        };
+        let original = GossipMessage::Chat {
+            name: "Alice".to_string(),
+            text: "look at this".to_string(),
+            ts: 1,
+            attachment: Some(att.clone()),
+        };
+        let serialized = serde_json::to_string(&original).unwrap();
+        let deserialized: GossipMessage = serde_json::from_str(&serialized).unwrap();
+        if let GossipMessage::Chat { attachment, .. } = deserialized {
+            assert_eq!(attachment, Some(att));
+        } else {
+            panic!("Expected GossipMessage::Chat");
+        }
+
+        // A pre-v2 chat payload (no `attachment` field) must still deserialize,
+        // defaulting the attachment to None (serde(default)).
+        let legacy = r#"{"Chat":{"name":"Old","text":"hi","ts":7}}"#;
+        let parsed: GossipMessage = serde_json::from_str(legacy).unwrap();
+        if let GossipMessage::Chat { name, attachment, .. } = parsed {
+            assert_eq!(name, "Old");
+            assert_eq!(attachment, None);
+        } else {
+            panic!("Expected GossipMessage::Chat");
+        }
+    }
+
    #[test]
    fn test_gossip_payload_chat_round_trip() {
        let secret = SecretKey::generate();
@@ -734,6 +843,7 @@ mod tests {
                name: "Bob".to_string(),
                text: "Hi there".to_string(),
                ts: 987654321,
+                attachment: None,
            },
        );

@@ -741,7 +851,7 @@ mod tests {
        let deserialized: GossipPayload = serde_json::from_str(&serialized).unwrap();

        assert_eq!(deserialized.author, secret.public());
-        if let GossipMessage::Chat { name, text, ts } = deserialized.msg {
+        if let GossipMessage::Chat { name, text, ts, .. } = deserialized.msg {
            assert_eq!(name, "Bob");
            assert_eq!(text, "Hi there");
            assert_eq!(ts, 987654321);
@@ -756,10 +866,11 @@ mod tests {
            name: "🎙 User".to_string(),
            text: "héllo 🎙 世界".to_string(),
            ts: 1717171717,
+            attachment: None,
        };
        let serialized = serde_json::to_string(&original).unwrap();
        let deserialized: GossipMessage = serde_json::from_str(&serialized).unwrap();
-        if let GossipMessage::Chat { name, text, ts } = deserialized {
+        if let GossipMessage::Chat { name, text, ts, .. } = deserialized {
            assert_eq!(name, "🎙 User");
            assert_eq!(text, "héllo 🎙 世界");
            assert_eq!(ts, 1717171717);
@@ -799,7 +910,7 @@ mod tests {
        let secret = SecretKey::generate();
        let topic = [4u8; 32];
        let mut p = sign_gossip(&secret, &topic, 5_000, GossipMessage::Leave);
-        p.msg = GossipMessage::Chat { name: "x".into(), text: "y".into(), ts: 5_000 };
+        p.msg = GossipMessage::Chat { name: "x".into(), text: "y".into(), ts: 5_000, attachment: None };
        assert_eq!(
            verify_gossip(&p, &topic, 5_000, GOSSIP_FRESHNESS_MS),
            Err(GossipReject::BadSignature)
@@ -872,8 +983,8 @@ mod tests {
    fn state_mutation_replay_gate_leaves_chat_ordering_untouched() {
        let author = fresh_id();
        let mut seen = HashMap::new();
-        let later_chat = GossipMessage::Chat { name: "A".into(), text: "later".into(), ts: 200 };
-        let earlier_chat = GossipMessage::Chat { name: "A".into(), text: "earlier".into(), ts: 100 };
+        let later_chat = GossipMessage::Chat { name: "A".into(), text: "later".into(), ts: 200, attachment: None };
+        let earlier_chat = GossipMessage::Chat { name: "A".into(), text: "earlier".into(), ts: 100, attachment: None };

        assert!(admit_state_mutation(&mut seen, author, &later_chat, 200));
        assert!(admit_state_mutation(&mut seen, author, &earlier_chat, 100));
@@ -9,7 +9,8 @@ use std::collections::{HashMap, HashSet};
 use std::time::Duration;
 use async_trait::async_trait;

-use crate::protocol::AUDIO_ALPN;
+use crate::protocol::{AUDIO_ALPN, FILES_ALPN};
+use crate::files::{AttachmentId, ChatAttachment};

 /// Per-peer datagram send queue depth. Audio is real-time, so a backlog is
 /// useless latency — keep it shallow and drop the oldest frame when full.
@@ -31,6 +32,10 @@ const MAX_BACKOFF: Duration = Duration::from_secs(5);
 /// already means "the peer closed this on purpose."
 const GOODBYE_CODE: u32 = 1;

+/// Bound on each phase (connect, read) of a chat-attachment fetch, so a slow or
+/// stalled sender can't hang the fetch indefinitely.
+const FILE_FETCH_TIMEOUT: Duration = Duration::from_secs(30);
+
 /// State shared between the transport, its protocol handler, and every per-peer
 /// supervisor task. One supervisor owns a peer's whole connection lifecycle.
 struct Shared {
@@ -60,6 +65,11 @@ struct Shared {
    /// verified gossip roster plus peers still inside reconnect grace; transport
    /// connections alone never mutate this set.
    admitted_audio: StdMutex<HashSet<EndpointId>>,
+    /// Chat file attachments we're serving to room members this session, keyed by
+    /// the random attachment id. Populated when we send a chat file; read by the
+    /// file protocol handler to answer a member's fetch. Cleared on leave. Each
+    /// blob is already byte-capped at send time.
+    served_files: StdMutex<HashMap<crate::files::AttachmentId, Arc<Vec<u8>>>>,
    incoming_tx: mpsc::Sender<(EndpointId, Bytes)>,
    /// Best-effort link-state notifications for the UI (connecting / connected).
    conn_events_tx: mpsc::Sender<ConnEvent>,
@@ -402,6 +412,88 @@ impl iroh::protocol::ProtocolHandler for AudioRouter {
    }
 }

+/// Protocol handler for the file-transfer plane (`FILES_ALPN`). Mirrors
+/// [`AudioRouter`]: it's persistent on the router and bound to the active
+/// session's [`Shared`] on join. On an inbound stream it authenticates the peer
+/// (iroh ALPN handshake gives us `remote_id`), gates on **live room membership**
+/// (same invariant as audio admission, so a former member can't pull files),
+/// reads a single 32-byte attachment id, and streams back the matching blob from
+/// the session serve store — or nothing if the id is unknown.
+#[derive(Clone, Default)]
+pub struct FileRouter {
+    current: Arc<StdMutex<Option<Arc<Shared>>>>,
+}
+
+impl std::fmt::Debug for FileRouter {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("FileRouter").finish_non_exhaustive()
+    }
+}
+
+impl FileRouter {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Route inbound file fetches to `transport`'s session (called on join).
+    pub fn bind(&self, transport: &IrohTransport) {
+        *self.current.lock().unwrap() = Some(transport.shared.clone());
+    }
+
+    /// Stop serving files until the next [`bind`](Self::bind) (called on leave).
+    pub fn clear(&self) {
+        *self.current.lock().unwrap() = None;
+    }
+}
+
+/// Max bytes we'll read for a fetch *request* frame. A request is exactly one
+/// 32-byte id; this small ceiling rejects a peer trying to stream us a huge
+/// "request" as a cheap DoS.
+const FILE_REQUEST_MAX: usize = 64;
+
+impl iroh::protocol::ProtocolHandler for FileRouter {
+    fn accept(
+        &self,
+        connection: Connection,
+    ) -> impl std::future::Future<Output = Result<(), iroh::protocol::AcceptError>> + Send {
+        let peer_id = connection.remote_id();
+        let shared = self.current.lock().unwrap().clone();
+        async move {
+            // No active call → nothing to serve.
+            let Some(shared) = shared else {
+                return Ok(());
+            };
+            // Member gating: only current room members may fetch our files. Reuses
+            // the audio admission roster (the authoritative room membership set).
+            if !shared.audio_sender_admitted(peer_id) {
+                crate::log_msg(&format!(
+                    "Transport: rejected file fetch from non-member {}",
+                    crate::short_id(&peer_id.to_string())
+                ));
+                return Ok(());
+            }
+            // Accept one bidirectional stream: read the id, write the bytes.
+            let Ok((mut send, mut recv)) = connection.accept_bi().await else {
+                return Ok(());
+            };
+            let Ok(req) = recv.read_to_end(FILE_REQUEST_MAX).await else {
+                return Ok(());
+            };
+            let Some(id) = crate::files::parse_request(&req) else {
+                return Ok(());
+            };
+            let blob = shared.served_files.lock().unwrap().get(&id).cloned();
+            if let Some(blob) = blob {
+                let _ = send.write_all(&blob).await;
+            }
+            // Finish either way: an unknown id closes with an empty body, which
+            // the fetcher reads as a zero-length result and treats as "gone".
+            let _ = send.finish();
+            Ok(())
+        }
+    }
+}
+
 pub struct IrohTransport {
    shared: Arc<Shared>,
    incoming_rx: tokio::sync::Mutex<Option<mpsc::Receiver<(EndpointId, Bytes)>>>,
@@ -426,6 +518,7 @@ impl IrohTransport {
            peers: tokio::sync::Mutex::new(HashMap::new()),
            live_conns: StdMutex::new(HashMap::new()),
            admitted_audio: StdMutex::new(HashSet::new()),
+            served_files: StdMutex::new(HashMap::new()),
            incoming_tx,
            conn_events_tx,
        });
@@ -455,6 +548,7 @@ impl IrohTransport {
        self.shared.senders.lock().unwrap().clear();
        self.shared.addrs.lock().unwrap().clear();
        self.shared.admitted_audio.lock().unwrap().clear();
+        self.shared.served_files.lock().unwrap().clear();
        // Give the CONNECTION_CLOSE frames a moment to flush before the caller
        // shuts the endpoint/router down (the `conns` clones are still alive
        // here, so the endpoint can still transmit them).
@@ -483,6 +577,59 @@ impl IrohTransport {
    pub fn audio_sender_admitted(&self, peer_id: EndpointId) -> bool {
        self.shared.audio_sender_admitted(peer_id)
    }
+
+    /// Make `bytes` available to room members under `id` for the rest of this
+    /// session (served by the [`FileRouter`] handler). Called by core when we
+    /// send a chat file. The blob is cleared on leave.
+    pub fn serve_attachment(&self, id: AttachmentId, bytes: Arc<Vec<u8>>) {
+        self.shared.served_files.lock().unwrap().insert(id, bytes);
+    }
+
+    /// Fetch a chat attachment's bytes from its sender over the file plane. Dials
+    /// the sender on `FILES_ALPN` (preferring a known full address), writes the
+    /// 32-byte id, and reads the response bounded by the descriptor's declared
+    /// size (which the caller has already validated against the global cap). The
+    /// read limit means a malicious sender can't stream us more than advertised.
+    pub async fn fetch_attachment(
+        &self,
+        from: EndpointId,
+        att: &ChatAttachment,
+    ) -> Result<Vec<u8>, NetError> {
+        if !crate::files::size_within_cap(att.size) {
+            return Err(NetError::Other("attachment size out of range".to_string()));
+        }
+        let addr = self.shared.addrs.lock().unwrap().get(&from).cloned();
+        let connect = async {
+            match addr {
+                Some(addr) => self.shared.endpoint.connect(addr, FILES_ALPN).await,
+                None => self.shared.endpoint.connect(from, FILES_ALPN).await,
+            }
+        };
+        let conn = tokio::time::timeout(FILE_FETCH_TIMEOUT, connect)
+            .await
+            .map_err(|_| NetError::Other("file fetch: connect timed out".to_string()))?
+            .map_err(|e| NetError::Other(format!("file fetch: connect failed: {e}")))?;
+
+        let (mut send, mut recv) = conn
+            .open_bi()
+            .await
+            .map_err(|e| NetError::Other(format!("file fetch: open stream failed: {e}")))?;
+        send.write_all(&att.id)
+            .await
+            .map_err(|e| NetError::Other(format!("file fetch: request write failed: {e}")))?;
+        send.finish()
+            .map_err(|e| NetError::Other(format!("file fetch: request finish failed: {e}")))?;
+
+        let read = recv.read_to_end(att.size as usize);
+        let bytes = tokio::time::timeout(FILE_FETCH_TIMEOUT, read)
+            .await
+            .map_err(|_| NetError::Other("file fetch: read timed out".to_string()))?
+            .map_err(|e| NetError::Other(format!("file fetch: read failed: {e}")))?;
+        if bytes.is_empty() {
+            return Err(NetError::Other("file fetch: sender no longer has the file".to_string()));
+        }
+        Ok(bytes)
+    }
 }

 #[async_trait]
@@ -57,7 +57,15 @@ pub enum RoomEvent {
    /// A peer sent a room text-chat message. Carries the sender's id, their
    /// display name (embedded so it shows even without a presence entry), the
    /// text, and a sender-stamped millisecond timestamp.
-    ChatMessage { from: EndpointId, name: String, text: String, ts: u64 },
+    ChatMessage {
+        from: EndpointId,
+        name: String,
+        text: String,
+        ts: u64,
+        /// Optional file attachment descriptor; the bytes are fetched off-gossip
+        /// on the file plane. Already filename-sanitized + size-capped on ingest.
+        attachment: Option<crate::files::ChatAttachment>,
+    },
 }

 /// Transport-level link state for a peer, surfaced so the UI can show when a
@@ -194,9 +202,25 @@ pub trait RoomState: Send + Sync {
    /// Updates our local state (e.g. when user mutes/unmutes) and broadcasts it.
    async fn update_self_state(&self, self_state: PeerState) -> Result<(), NetError>;

+    /// Ask the active gossip topic to connect to retained peer addresses without
+    /// leaving or replacing the subscription. This is a recovery primitive only:
+    /// it does not add peers to the authenticated room roster. A peer becomes
+    /// active only after its normal signed `Announce` is received and verified.
+    async fn rebootstrap_peers(&self, peers: Vec<EndpointAddr>) -> Result<(), NetError>;
+
+    /// Remove a peer from the authenticated live roster before background
+    /// recovery. This only revokes membership; a fresh verified `Announce` is
+    /// required to add the peer again.
+    fn mark_peer_disconnected(&self, peer_id: EndpointId);
+
    /// Broadcasts a room text-chat message authored by us (our display name is
-    /// taken from the current self-state).
-    async fn send_chat(&self, text: String) -> Result<(), NetError>;
+    /// taken from the current self-state), optionally carrying a file attachment
+    /// descriptor whose bytes are served separately on the file plane.
+    async fn send_chat(
+        &self,
+        text: String,
+        attachment: Option<crate::files::ChatAttachment>,
+    ) -> Result<(), NetError>;

    /// Leaves the room and announces departure.
    async fn leave(&self) -> Result<(), NetError>;
@@ -342,4 +366,3 @@ mod tests {
        assert_eq!(original, deserialized);
    }
 }
-
@@ -3,11 +3,12 @@
 //!
 //! The WAVs are embedded in the binary (`include_bytes!`) so a deployed single
 //! binary is self-contained — no asset directory to ship alongside it. On first
-//! use each sound is written once to a temp file, then played fire-and-forget
-//! via `pw-play` (PipeWire-native; falls back to `paplay`/`aplay`). Playback runs
-//! on a detached thread that waits on the child, so it never blocks the UI and
-//! never leaves a zombie. Any failure (no player, no audio) is silent by design —
-//! a missing chime should never disrupt a call.
+//! use each sound is written once to a temp file, then played fire-and-forget.
+//! Linux uses `pw-play` (PipeWire-native; falls back to `paplay`/`aplay`);
+//! Windows uses PowerShell's `System.Media.SoundPlayer`. Playback runs on a
+//! detached thread that waits on the child, so it never blocks the UI and never
+//! leaves a zombie. Any failure (no player, no audio) is silent by design — a
+//! missing chime should never disrupt a call.

 use std::collections::HashMap;
 use std::path::{Path, PathBuf};
@@ -202,8 +203,14 @@ fn cached_path(sound: Sound) -> Option<PathBuf> {
    Some(path)
 }

+#[cfg(any(windows, test))]
+fn escape_powershell_single_quoted(s: &str) -> String {
+    s.replace('\'', "''")
+}
+
 /// Try each available player in turn, waiting on the first that starts (which
 /// reaps the child). Runs on a detached thread, so the wait is harmless.
+#[cfg(not(windows))]
 fn spawn_player(path: &Path) {
    for player in ["pw-play", "paplay", "aplay"] {
        let started = Command::new(player)
@@ -221,6 +228,23 @@ fn spawn_player(path: &Path) {
    }
 }

+/// Play through Windows' built-in WAV player. Runs on a detached thread, so
+/// `PlaySync()` blocking for the sound duration is fine.
+#[cfg(windows)]
+fn spawn_player(path: &Path) {
+    let path = escape_powershell_single_quoted(&path.display().to_string());
+    let command = format!("(New-Object System.Media.SoundPlayer '{path}').PlaySync()");
+    let _ = Command::new("powershell")
+        .arg("-NoProfile")
+        .arg("-NonInteractive")
+        .arg("-Command")
+        .arg(command)
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .status();
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;
@@ -234,6 +258,18 @@ mod tests {
        assert!(!should_play(false, false));
    }

+    #[test]
+    fn test_powershell_single_quote_escape() {
+        assert_eq!(
+            escape_powershell_single_quoted(r"C:\Users\O'Brien\chime.wav"),
+            r"C:\Users\O''Brien\chime.wav"
+        );
+        assert_eq!(
+            escape_powershell_single_quoted("a'b'c"),
+            "a''b''c"
+        );
+    }
+
    #[test]
    fn test_sound_indices_unique_and_match_all() {
        // `index()` must be a 0..COUNT bijection in `ALL` order, or the flag
@@ -22,16 +22,26 @@ pub const FRIENDS_PROTO: u32 = 1;
 /// Gossip plane version (`GossipPayload`/`GossipMessage`/`PeerState`, signing,
 /// freshness). Bump on any change. Mirrored in [`GOSSIP_SIG_DOMAIN`] and folded
 /// into [`versioned_topic`].
-pub const GOSSIP_PROTO: u32 = 1;
+///
+/// v2 (0.3.0): `GossipMessage::Chat` gained an optional file attachment
+/// (`ChatAttachment`), so a pre-v2 peer can't interpret/serve chat files — bumped
+/// to fail fast rather than half-work.
+pub const GOSSIP_PROTO: u32 = 2;
+/// File-transfer plane version (chat attachment request/stream shape). Bump on
+/// any change. Mirrored in [`FILES_ALPN`].
+pub const FILES_PROTO: u32 = 1;

 /// ALPN for the audio datagram plane: `peerspeak/audio/<AUDIO_PROTO>`.
 pub const AUDIO_ALPN: &[u8] = b"peerspeak/audio/1";
 /// ALPN for the friends/presence plane: `peerspeak/friends/<FRIENDS_PROTO>`.
 pub const FRIENDS_ALPN: &[u8] = b"peerspeak/friends/1";
+/// ALPN for the file-transfer plane: `peerspeak/files/<FILES_PROTO>`. Carries
+/// chat attachment bytes via direct QUIC streams (not gossip).
+pub const FILES_ALPN: &[u8] = b"peerspeak/files/1";
 /// ed25519 gossip signature domain: `peerspeak-gossip-v<GOSSIP_PROTO>`. Carries
 /// the gossip protocol version into every signed payload — a version mismatch
 /// fails verification (cryptographic separation between gossip versions).
-pub const GOSSIP_SIG_DOMAIN: &str = "peerspeak-gossip-v1";
+pub const GOSSIP_SIG_DOMAIN: &str = "peerspeak-gossip-v2";

 /// Version-namespace a room topic so peers on different gossip protocol versions
 /// derive **different subscription topics from the same ticket** and therefore
@@ -62,6 +72,7 @@ mod tests {
    fn alpns_match_their_proto_versions() {
        assert_eq!(AUDIO_ALPN, format!("peerspeak/audio/{AUDIO_PROTO}").as_bytes());
        assert_eq!(FRIENDS_ALPN, format!("peerspeak/friends/{FRIENDS_PROTO}").as_bytes());
+        assert_eq!(FILES_ALPN, format!("peerspeak/files/{FILES_PROTO}").as_bytes());
        assert_eq!(GOSSIP_SIG_DOMAIN, format!("peerspeak-gossip-v{GOSSIP_PROTO}"));
    }

@@ -25,6 +25,16 @@ use tokio::process::{Child, Command};
 /// points elsewhere.
 const PIXELPASS_BIN: &str = "pixelpass";

+#[cfg(windows)]
+fn pixelpass_path_candidates(dir: &Path) -> [PathBuf; 2] {
+    [dir.join(PIXELPASS_BIN), dir.join("pixelpass.exe")]
+}
+
+#[cfg(not(windows))]
+fn pixelpass_path_candidates(dir: &Path) -> [PathBuf; 1] {
+    [dir.join(PIXELPASS_BIN)]
+}
+
 /// Pixelpass endpoint tickets are normally ~140 chars. Leave headroom for format
 /// growth, but reject unbounded gossip payloads before the UI offers "Watch".
 const MAX_TICKET_LEN: usize = 512;
@@ -143,7 +153,7 @@ pub fn pixelpass_path(config_override: Option<&str>) -> Option<PathBuf> {
    }
    let path_var = std::env::var_os("PATH")?;
    std::env::split_paths(&path_var)
-        .map(|dir| dir.join(PIXELPASS_BIN))
+        .flat_map(|dir| pixelpass_path_candidates(&dir))
        .find(|c| c.is_file())
 }

@@ -513,4 +523,14 @@ mod tests {
        // only assert it doesn't return the empty path as a match.
        assert_ne!(pixelpass_path(Some("   ")).as_deref(), Some(Path::new("")));
    }
+
+    #[test]
+    fn pixelpass_path_candidates_are_platform_specific() {
+        let dir = Path::new("bin");
+        let candidates: Vec<PathBuf> = pixelpass_path_candidates(dir).into_iter().collect();
+        #[cfg(windows)]
+        assert_eq!(candidates, vec![dir.join("pixelpass"), dir.join("pixelpass.exe")]);
+        #[cfg(not(windows))]
+        assert_eq!(candidates, vec![dir.join("pixelpass")]);
+    }
 }
@@ -60,6 +60,9 @@ pub enum AppTheme {
    GruvboxDark,
    SolarizedLight,
    GruvboxLight,
+    AyuDark,
+    AyuMirage,
+    AyuLight,
 }

 /// Build a `Color` from a packed `0xRRGGBB` literal — keeps the palette tables
@@ -70,7 +73,7 @@ fn hex(c: u32) -> Color {

 impl AppTheme {
    /// Every theme, in picker order.
-    pub const ALL: [AppTheme; 10] = [
+    pub const ALL: [AppTheme; 13] = [
        AppTheme::Mocha,
        AppTheme::Macchiato,
        AppTheme::Frappe,
@@ -81,6 +84,9 @@ impl AppTheme {
        AppTheme::GruvboxDark,
        AppTheme::SolarizedLight,
        AppTheme::GruvboxLight,
+        AppTheme::AyuDark,
+        AppTheme::AyuMirage,
+        AppTheme::AyuLight,
    ];

    /// Human-readable name for the picker.
@@ -96,6 +102,9 @@ impl AppTheme {
            AppTheme::GruvboxDark => "Gruvbox Dark",
            AppTheme::SolarizedLight => "Solarized Light",
            AppTheme::GruvboxLight => "Gruvbox Light",
+            AppTheme::AyuDark => "Ayu Dark",
+            AppTheme::AyuMirage => "Ayu Mirage",
+            AppTheme::AyuLight => "Ayu Light",
        }
    }

@@ -103,7 +112,10 @@ impl AppTheme {
    pub fn is_dark(self) -> bool {
        !matches!(
            self,
-            AppTheme::Latte | AppTheme::SolarizedLight | AppTheme::GruvboxLight
+            AppTheme::Latte
+                | AppTheme::SolarizedLight
+                | AppTheme::GruvboxLight
+                | AppTheme::AyuLight
        )
    }

@@ -120,6 +132,8 @@ impl AppTheme {
            AppTheme::GruvboxDark => iced::Theme::GruvboxDark,
            AppTheme::SolarizedLight => iced::Theme::SolarizedLight,
            AppTheme::GruvboxLight => iced::Theme::GruvboxLight,
+            AppTheme::AyuDark | AppTheme::AyuMirage => iced::Theme::TokyoNight,
+            AppTheme::AyuLight => iced::Theme::Light,
        }
    }

@@ -281,6 +295,52 @@ impl AppTheme {
                green: hex(0x79740e),
                yellow: hex(0xb57614),
            },
+            AppTheme::AyuDark => Palette {
+                crust: hex(0x06080a),
+                mantle: hex(0x0b0e14),
+                base: hex(0x0d1017),
+                surface: hex(0x1c222b),
+                overlay: hex(0x565b66),
+                text: hex(0xbfbdb6),
+                subtext: hex(0x9da1a6),
+                blue: hex(0xe6b450),
+                lavender: hex(0x59c2ff),
+                red: hex(0xf07178),
+                maroon: hex(0xff8f40),
+                green: hex(0xaad94c),
+                yellow: hex(0xffb454),
+            },
+            AppTheme::AyuMirage => Palette {
+                crust: hex(0x171b24),
+                mantle: hex(0x1a1f29),
+                base: hex(0x1f2430),
+                surface: hex(0x232834),
+                overlay: hex(0x707a8c),
+                text: hex(0xcccac2),
+                subtext: hex(0xa6abb4),
+                blue: hex(0xffcc66),
+                lavender: hex(0x73d0ff),
+                red: hex(0xf28779),
+                maroon: hex(0xffa759),
+                green: hex(0xd5ff80),
+                yellow: hex(0xffd173),
+            },
+            // Ayu Light's canonical orange is deepened for legibility on white.
+            AppTheme::AyuLight => Palette {
+                crust: hex(0xe6e9ec),
+                mantle: hex(0xf3f4f5),
+                base: hex(0xfcfcfc),
+                surface: hex(0xe8eaed),
+                overlay: hex(0x8a9199),
+                text: hex(0x5c6166),
+                subtext: hex(0x737980),
+                blue: hex(0xc7500e),
+                lavender: hex(0x399ee6),
+                red: hex(0xf07171),
+                maroon: hex(0xfa8d3e),
+                green: hex(0x86b300),
+                yellow: hex(0xff9940),
+            },
        }
    }
 }
@@ -371,11 +431,11 @@ mod tests {
    fn all_themes_distinct_and_labeled() {
        // ALL covers exactly the variants once, each with a unique non-empty label
        // and a distinct base colour (so swatches don't look identical).
-        assert_eq!(AppTheme::ALL.len(), 10);
+        assert_eq!(AppTheme::ALL.len(), 13);
        let mut labels: Vec<&str> = AppTheme::ALL.iter().map(|t| t.label()).collect();
        labels.sort_unstable();
        labels.dedup();
-        assert_eq!(labels.len(), 10, "labels must be unique + non-empty");
+        assert_eq!(labels.len(), 13, "labels must be unique + non-empty");
        assert!(labels.iter().all(|l| !l.is_empty()));
    }

@@ -0,0 +1,354 @@
+//! Phase-0 spike for post-grace gossip recovery.
+//!
+//! These tests prove that `GossipSender::join_peers` can restore an existing
+//! topic subscription after the other peer drops and rejoins without its own
+//! bootstrap target. The second case disables relays, clears the surviving
+//! node's lookup, and moves the peer to a fresh endpoint address so only the
+//! retained full address passed to `rebootstrap_peers` can drive recovery.
+
+use std::sync::Arc;
+use std::time::Duration;
+
+use iroh::address_lookup::memory::MemoryLookup;
+use iroh::endpoint::presets;
+use iroh::protocol::Router;
+use iroh::{Endpoint, EndpointAddr, EndpointId, RelayMode, SecretKey};
+use iroh_gossip::net::Gossip;
+use tokio::sync::mpsc;
+
+use peerspeak::network::gossip::IrohGossipState;
+use peerspeak::network::{PeerSpeakTicket, PeerState, RoomEvent, RoomState};
+
+const EVENT_TIMEOUT: Duration = Duration::from_secs(10);
+
+struct GossipNode {
+    endpoint: Endpoint,
+    lookup: MemoryLookup,
+    room: Arc<IrohGossipState>,
+    _router: Router,
+}
+
+async fn spawn_node(secret: SecretKey) -> GossipNode {
+    let lookup = MemoryLookup::new();
+    let endpoint = Endpoint::builder(presets::Minimal)
+        .secret_key(secret.clone())
+        .relay_mode(RelayMode::Disabled)
+        .address_lookup(lookup.clone())
+        .bind()
+        .await
+        .expect("bind gossip endpoint");
+    let gossip = Gossip::builder().spawn(endpoint.clone());
+    let router = Router::builder(endpoint.clone())
+        .accept(iroh_gossip::net::GOSSIP_ALPN, gossip.clone())
+        .spawn();
+    let room = Arc::new(IrohGossipState::new(
+        endpoint.clone(),
+        gossip,
+        lookup.clone(),
+        secret,
+    ));
+
+    GossipNode {
+        endpoint,
+        lookup,
+        room,
+        _router: router,
+    }
+}
+
+fn state(name: &str, addr: EndpointAddr) -> PeerState {
+    PeerState {
+        name: name.to_string(),
+        is_muted: false,
+        addr,
+        sharing: None,
+        avatar: Default::default(),
+    }
+}
+
+async fn await_joined(rx: &mut mpsc::Receiver<RoomEvent>, peer_id: EndpointId) -> PeerState {
+    let deadline = tokio::time::Instant::now() + EVENT_TIMEOUT;
+    loop {
+        match tokio::time::timeout_at(deadline, rx.recv()).await {
+            Ok(Some(RoomEvent::PeerJoined(id, peer_state))) if id == peer_id => return peer_state,
+            Ok(Some(_)) => continue,
+            Ok(None) => panic!("room event channel closed while waiting for PeerJoined"),
+            Err(_) => panic!("timed out waiting for PeerJoined({peer_id:?})"),
+        }
+    }
+}
+
+async fn await_joined_all(rx: &mut mpsc::Receiver<RoomEvent>, peer_ids: &[EndpointId]) {
+    let deadline = tokio::time::Instant::now() + EVENT_TIMEOUT;
+    let mut remaining = peer_ids.to_vec();
+    while !remaining.is_empty() {
+        match tokio::time::timeout_at(deadline, rx.recv()).await {
+            Ok(Some(RoomEvent::PeerJoined(id, _))) => remaining.retain(|wanted| *wanted != id),
+            Ok(Some(_)) => {}
+            Ok(None) => panic!("room event channel closed while waiting for PeerJoined set"),
+            Err(_) => panic!("timed out waiting for PeerJoined set: {remaining:?}"),
+        }
+    }
+}
+
+async fn await_left(rx: &mut mpsc::Receiver<RoomEvent>, peer_id: EndpointId) {
+    let deadline = tokio::time::Instant::now() + EVENT_TIMEOUT;
+    loop {
+        match tokio::time::timeout_at(deadline, rx.recv()).await {
+            Ok(Some(RoomEvent::PeerLeft(id))) if id == peer_id => return,
+            Ok(Some(_)) => continue,
+            Ok(None) => panic!("room event channel closed while waiting for PeerLeft"),
+            Err(_) => panic!("timed out waiting for PeerLeft({peer_id:?})"),
+        }
+    }
+}
+
+async fn await_absent(room: &IrohGossipState, peer_id: EndpointId) {
+    let deadline = tokio::time::Instant::now() + EVENT_TIMEOUT;
+    loop {
+        if !room.active_peers().iter().any(|(id, _)| *id == peer_id) {
+            return;
+        }
+        assert!(
+            tokio::time::Instant::now() < deadline,
+            "timed out waiting for peer to leave the roster"
+        );
+        tokio::time::sleep(Duration::from_millis(20)).await;
+    }
+}
+
+fn ticket(host_addr: EndpointAddr) -> String {
+    PeerSpeakTicket {
+        host_addr,
+        topic_id: rand::random(),
+        name: "rebootstrap-spike".to_string(),
+    }
+    .to_string()
+}
+
+async fn establish_room(
+    a: &GossipNode,
+    b: &GossipNode,
+    ticket: &str,
+    events_a: &mut mpsc::Receiver<RoomEvent>,
+) {
+    // B is the ticket host. Its own bootstrap set is empty; A is the only side
+    // that initially dials, which is also how the recovery setup is controlled.
+    b.room
+        .join(ticket, state("Bob", b.endpoint.addr()), vec![])
+        .await
+        .expect("host joins topic");
+    a.room
+        .join(ticket, state("Alice", a.endpoint.addr()), vec![])
+        .await
+        .expect("client joins topic");
+    let joined = await_joined(events_a, b.endpoint.id()).await;
+    assert_eq!(joined.name, "Bob");
+}
+
+#[tokio::test]
+async fn rebootstrap_restores_roster_on_existing_subscription() {
+    let a = spawn_node(SecretKey::generate()).await;
+    let b = spawn_node(SecretKey::generate()).await;
+    let ticket = ticket(b.endpoint.addr());
+    let mut events_a = a.room.subscribe_events().await.expect("subscribe A events");
+
+    establish_room(&a, &b, &ticket, &mut events_a).await;
+
+    // Drop only B's topic subscription. A stays subscribed. B then rejoins as
+    // the ticket host, so compute_bootstrap removes self and B has nobody to dial.
+    b.room.leave().await.expect("B leaves topic");
+    await_absent(&a.room, b.endpoint.id()).await;
+    b.room
+        .join(&ticket, state("Bob recovered", b.endpoint.addr()), vec![])
+        .await
+        .expect("B rejoins without bootstrap peers");
+
+    tokio::time::sleep(Duration::from_millis(250)).await;
+    assert!(
+        !a.room
+            .active_peers()
+            .iter()
+            .any(|(id, _)| *id == b.endpoint.id()),
+        "B must not recover before A explicitly re-bootstraps it"
+    );
+
+    a.room
+        .rebootstrap_peers(vec![b.endpoint.addr()])
+        .await
+        .expect("targeted gossip re-bootstrap");
+
+    let recovered = await_joined(&mut events_a, b.endpoint.id()).await;
+    assert_eq!(recovered.name, "Bob recovered");
+}
+
+#[tokio::test]
+async fn rebootstrap_uses_retained_full_address_with_empty_lookup() {
+    let a = spawn_node(SecretKey::generate()).await;
+    let b_secret = SecretKey::generate();
+    let b = spawn_node(b_secret.clone()).await;
+    let b_id = b.endpoint.id();
+    let old_b_addr = b.endpoint.addr();
+    let ticket = ticket(old_b_addr.clone());
+    let mut events_a = a.room.subscribe_events().await.expect("subscribe A events");
+
+    establish_room(&a, &b, &ticket, &mut events_a).await;
+    b.room.leave().await.expect("old B leaves topic");
+    await_absent(&a.room, b_id).await;
+
+    // Move the same authenticated identity to a newly-bound direct-only endpoint.
+    // The old cached path is now dead; the new full address is the only valid one.
+    b.endpoint.close().await;
+    drop(b);
+    tokio::time::sleep(Duration::from_millis(250)).await;
+    let b_rebound = spawn_node(b_secret).await;
+    let new_b_addr = b_rebound.endpoint.addr();
+    assert_eq!(new_b_addr.id, b_id, "identity must survive the rebind");
+    assert_ne!(
+        new_b_addr, old_b_addr,
+        "rebound peer must have a fresh address"
+    );
+
+    b_rebound
+        .room
+        .join(&ticket, state("Bob rebound", new_b_addr.clone()), vec![])
+        .await
+        .expect("rebound host joins without bootstrap peers");
+
+    // Remove the stale lookup entry. `rebootstrap_peers` must seed the retained
+    // new full address before asking gossip to join the peer by id.
+    a.lookup.remove_endpoint_info(b_id);
+    assert!(
+        a.lookup.get_endpoint_info(b_id).is_none(),
+        "A lookup starts empty for B"
+    );
+    tokio::time::sleep(Duration::from_millis(250)).await;
+    assert!(
+        !a.room.active_peers().iter().any(|(id, _)| *id == b_id),
+        "rebound B must not be rediscovered without the retained address"
+    );
+
+    a.room
+        .rebootstrap_peers(vec![new_b_addr])
+        .await
+        .expect("retained-address gossip re-bootstrap");
+    assert!(
+        a.lookup.get_endpoint_info(b_id).is_some(),
+        "re-bootstrap must restore B's address to the lookup"
+    );
+
+    let recovered = await_joined(&mut events_a, b_id).await;
+    assert_eq!(recovered.name, "Bob rebound");
+}
+
+#[tokio::test]
+async fn demoted_peer_requires_a_fresh_signed_announce_to_rejoin() {
+    let a = spawn_node(SecretKey::generate()).await;
+    let b = spawn_node(SecretKey::generate()).await;
+    let ticket = ticket(b.endpoint.addr());
+    let mut events_a = a.room.subscribe_events().await.expect("subscribe A events");
+
+    establish_room(&a, &b, &ticket, &mut events_a).await;
+    a.room.mark_peer_disconnected(b.endpoint.id());
+    assert!(
+        !a.room
+            .active_peers()
+            .iter()
+            .any(|(id, _)| *id == b.endpoint.id()),
+        "demotion must revoke live roster membership"
+    );
+
+    b.room
+        .update_self_state(state("Bob authenticated again", b.endpoint.addr()))
+        .await
+        .expect("broadcast fresh signed announce");
+
+    let recovered = await_joined(&mut events_a, b.endpoint.id()).await;
+    assert_eq!(recovered.name, "Bob authenticated again");
+}
+
+#[tokio::test]
+async fn signed_leave_after_demotion_still_emits_peer_left() {
+    let a = spawn_node(SecretKey::generate()).await;
+    let b = spawn_node(SecretKey::generate()).await;
+    let ticket = ticket(b.endpoint.addr());
+    let mut events_a = a.room.subscribe_events().await.expect("subscribe A events");
+
+    establish_room(&a, &b, &ticket, &mut events_a).await;
+    a.room.mark_peer_disconnected(b.endpoint.id());
+
+    b.room
+        .leave()
+        .await
+        .expect("broadcast signed Leave after demotion");
+    await_left(&mut events_a, b.endpoint.id()).await;
+}
+
+#[tokio::test]
+async fn targeted_rebootstrap_preserves_healthy_peer_in_three_peer_room() {
+    let a = spawn_node(SecretKey::generate()).await;
+    let b = spawn_node(SecretKey::generate()).await;
+    let c_secret = SecretKey::generate();
+    let c = spawn_node(c_secret.clone()).await;
+    let c_id = c.endpoint.id();
+    let ticket = ticket(c.endpoint.addr());
+    let mut events_a = a.room.subscribe_events().await.expect("subscribe A events");
+    let mut events_b = b.room.subscribe_events().await.expect("subscribe B events");
+
+    c.room
+        .join(&ticket, state("Carol", c.endpoint.addr()), vec![])
+        .await
+        .expect("C hosts topic");
+    b.room
+        .join(&ticket, state("Bob", b.endpoint.addr()), vec![])
+        .await
+        .expect("B joins C");
+    await_joined(&mut events_b, c_id).await;
+    a.room
+        .join(&ticket, state("Alice", a.endpoint.addr()), vec![])
+        .await
+        .expect("A joins C");
+    await_joined_all(&mut events_a, &[b.endpoint.id(), c_id]).await;
+    await_joined(&mut events_b, a.endpoint.id()).await;
+
+    // Remove only C. A and B keep their existing topic subscriptions and remain
+    // mutually present while C is rebound to a fresh address.
+    c.endpoint.close().await;
+    drop(c);
+    a.room.mark_peer_disconnected(c_id);
+    b.room.mark_peer_disconnected(c_id);
+    let c_rebound = spawn_node(c_secret).await;
+    let rebound_addr = c_rebound.endpoint.addr();
+    c_rebound
+        .room
+        .join(
+            &ticket,
+            state("Carol recovered", rebound_addr.clone()),
+            vec![],
+        )
+        .await
+        .expect("rebound C rejoins as host without bootstrap");
+
+    a.room
+        .rebootstrap_peers(vec![rebound_addr])
+        .await
+        .expect("A targets only C for recovery");
+    let recovered = await_joined(&mut events_a, c_id).await;
+    assert_eq!(recovered.name, "Carol recovered");
+    await_joined(&mut events_b, c_id).await;
+
+    assert!(
+        a.room
+            .active_peers()
+            .iter()
+            .any(|(id, _)| *id == b.endpoint.id()),
+        "healthy B must remain present at A throughout C recovery"
+    );
+    assert!(
+        b.room
+            .active_peers()
+            .iter()
+            .any(|(id, _)| *id == a.endpoint.id()),
+        "healthy A must remain present at B throughout C recovery"
+    );
+}
@@ -25,8 +25,7 @@ use peerspeak::codec::opus_impl::OpusEncoder;
 use peerspeak::core::jitter::{FRAME_SAMPLES, JitterBuffer};
 use peerspeak::network::{ConnEvent, NetworkTransport};
 use peerspeak::network::iroh_impl::{AudioRouter, IrohTransport};
-
-const AUDIO_ALPN: &[u8] = b"peerspeak-audio";
+use peerspeak::protocol::AUDIO_ALPN;

 struct Node {
    endpoint: Endpoint,
@@ -0,0 +1,17 @@
+#!/bin/bash
+# Cross-compile peerspeak to x86_64-pc-windows-gnu (run inside the peerspeak-win distrobox).
+# Produces a statically-linked, self-contained .exe (no extra DLLs) for the
+# Windows installer in packaging/windows/. Requires the rust-src component and
+# the x86_64-pc-windows-gnu target; invoke with build-std for the static link:
+#   RUSTC_BOOTSTRAP=1 ./win-cross-build.sh -Z build-std=std,panic_abort
+set -euo pipefail
+cd "$(dirname "$0")"
+
+export CARGO_TARGET_X86_64_PC_WINDOWS_GNU_LINKER=x86_64-w64-mingw32-gcc
+export CC_x86_64_pc_windows_gnu=x86_64-w64-mingw32-gcc
+export CXX_x86_64_pc_windows_gnu=x86_64-w64-mingw32-g++
+export AR_x86_64_pc_windows_gnu=x86_64-w64-mingw32-ar
+# Bundled libopus declares cmake_minimum_required < 3.5; cmake 4.x refuses it.
+export CMAKE_POLICY_VERSION_MINIMUM=3.5
+
+cargo build --release --target x86_64-pc-windows-gnu --bin peerspeak "$@"