refactor: rename service to autostart, fix fork bomb, add rfd file picker, use dirs crate, auto-start launcher, propagate overlays, ensure icon

- Rename service module to autostart (no systemd service is used)
- Fix fork bomb: replace subprocess spawning with thread::spawn
- Replace zenity/kdialog with rfd crate for XDG Portal file picker
- Use dirs crate instead of env::var("HOME")
- Auto-start launcher before game launch for online auth
- Propagate gamemode/mangohud env vars to launcher process
- Auto-install SVG icon on startup via ensure_icon()
- Add assets/umutray.svg
- Remove stale zenity/kdialog optdepends from PKGBUILD
- Update .gitignore for .claude/ and CLAUDE.md

packaging/PKGBUILD

@@ -20,8 +20,6 @@ license=('MIT')
 depends=('umu-launcher')
 makedepends=('rust' 'cargo')
 optdepends=(
-    'zenity: folder picker in setup wizard (GNOME/GTK)'
-    'kdialog: folder picker in setup wizard (KDE)'
     'gamemode: per-game GameMode support'
     'mangohud: per-game MangoHud overlay'
     'gamescope: per-game Gamescope compositor'
@@ -54,6 +52,9 @@ package() {
     # App menu entry
     install -Dm644 umutray.desktop "$pkgdir/usr/share/applications/umutray.desktop"
 
+    # Icon
+    install -Dm644 assets/umutray.svg "$pkgdir/usr/share/icons/hicolor/scalable/apps/umutray.svg"
+
     # License
     install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
 }