Windows: notification chimes via SoundPlayer + docs/WINDOWS.md (W8)

Implemented by Codex (gpt-5.5); reviewed and committed by Claude.

W8 — chimes were played by shelling out to pw-play/paplay/aplay, which don't
exist on Windows, so every chime silently no-op'd there. spawn_player is now
cfg-split: Linux/unix keeps the existing player list; Windows plays the WAV via
PowerShell's System.Media.SoundPlayer (PlaySync on the existing detached thread).
Dependency-free, same fire-and-forget / silent-on-failure contract. Custom chime
paths are single-quote-escaped for the PowerShell command (helper + unit test).

Also adds docs/WINDOWS.md: a build/run/status guide (native MSVC + cross-compile
to -gnu, first-run firewall/UDP note, %APPDATA% paths, and the honest known-gaps
table — echo-cancel/screenshare/resampling/device-id/buffer-pacing).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/WINDOWS.md

@@ -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 | Open. Devices must support 48 kHz, and output must support stereo; a 44.1 kHz-only/default device currently errors instead of playing. |
+| Device persistence | Open. WASAPI friendly names may duplicate or change across driver/profile changes. |
+| Playback pacing | Open. The fixed playback target under WASAPI shared mode still needs real-hardware verification. |
+
+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.

src/notify.rs

@@ -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
+//! 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
+//! Linux uses `pw-play` (PipeWire-native; falls back to `paplay`/`aplay`);
-//! on a detached thread that waits on the child, so it never blocks the UI and
+//! Windows uses PowerShell's `System.Media.SoundPlayer`. Playback runs on a
-//! never leaves a zombie. Any failure (no player, no audio) is silent by design —
+//! detached thread that waits on the child, so it never blocks the UI and never
-//! a missing chime should never disrupt a call.
+//! 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