feat(gui): hand-rolled winit loop for true window-hide on Wayland

Replace eframe::run_native with a winit ApplicationHandler + glutin +
egui_glow loop so "keep running in the tray" can genuinely hide the
window. winit's set_visible(false) is a deliberate no-op on Wayland
(xdg-shell has no unmap-but-keep-alive request), so the only way to hide
a toplevel is to destroy its surface: hide-to-tray now drops the Window +
GL surface (parking the GL context as not-current) and a tray click
recreates them and makes the context current again. The GL context,
glutin display/config, egui_glow painter (uploaded textures), and
egui-winit state (clipboard) all persist across the cycle — only the OS
window and its surface churn.

Wakeups route through winit's EventLoopProxy (the new Waker, and the
tray) instead of egui's repaint callback, so a child event or tray click
wakes the loop even while the window is dropped and no frame is running —
keeping viewer join/leave notifications and the tray tooltip live while
hidden. Removes the old Wayland minimize-to-tray fallback (window stayed
in the taskbar); hide is now uniform on Wayland and X11.

Deps: winit/glutin/glutin-winit/egui_glow promoted to direct (gui-gated,
optional) — all already transitive via eframe, so no new crates. winit's
default features minus wayland-csd-adwaita, so sctk-adwaita/tiny-skia/
ttf-parser aren't pulled for a CSD fallback titlebar (KWin draws
server-side decorations, and eframe never had CSD either).

Verified end-to-end on KWin Wayland: launch->render; close->window AND
taskbar entry gone (true hide, process stays alive); tray activate->
window + GL surface recreated and renders; tray quit->clean exit; stderr
clean throughout. cargo test --features gui: 15 pass; clippy clean;
headless dependency tree unchanged.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Cargo.lock

@@ -1501,6 +1501,7 @@ checksum = "6caa4eca47cc2358e2c5ae60843a94118e338f87099c6af4170e6e968e8d77cb"
 dependencies = [
  "bytemuck",
  "egui",
+ "egui-winit",
  "glow",
  "log",
  "memoffset",
@@ -4166,6 +4167,9 @@ dependencies = [
  "dialoguer",
  "directories",
  "eframe",
+ "egui_glow",
+ "glutin",
+ "glutin-winit",
  "iroh",
  "iroh-tickets",
  "ksni",
@@ -4182,6 +4186,7 @@ dependencies = [
  "tracing-subscriber",
  "ureq",
  "uuid",
+ "winit",
  "x11rb",
 ]