feat(desktop): Linux AppImage releases and desktop feature parity (#2398)

* feat(electron): add Linux AppImage releases

* ci: cache Linux OpenCode CLI artifacts

* fix(ci): await Linux release inventory check

* fix(electron): add frameless window controls on Linux desktop

Linux AppImages were created without native WM decorations and without
in-app controls, leaving users unable to close the window with a mouse.

Treat Linux like Windows: frameless BrowserWindow plus the existing
WindowsWindowControls header buttons and app-menu entry. macOS keeps
hidden title bar with traffic lights unchanged.

Shared usesFramelessElectronChrome() helper drives main window, mini
chat, header insets, and titlebar controls.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* Linux desktop feature parity: Open in, background start, tray, multi-window (#2392)

* feat(electron): Linux parity for Open in, background start, and tray

Enable Linux desktop feature parity with macOS/Windows: open projects in
the default file manager and discovered apps, XDG autostart with
--background launches, system tray (including minimize-to-tray), and
tray sync from the renderer.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* fix(electron): allow packaged UI protocol navigations on Linux

Prevent openchamber-ui:// navigations from being handed to
shell.openExternal, which fails on Linux and blocked desktop UI flows.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* fix(ui): surface Linux tray settings in settings search

Include isLinux in settings search runtime context so minimize-to-tray
is discoverable on Linux desktop, matching Windows search behavior.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* fix(electron): stop Linux AppImage Waiting-for-OpenCode flicker

Sync updated boot-outcome init scripts to all BrowserWindows after
desktop_hosts_set, and prefer state.initScript on dom-ready so chooser
reloads inject local/ok instead of a stale not-configured outcome.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* fix(desktop): restore Linux AppImage updater feed and error UX (#2396)

Treat missing latest-linux*.yml (404) as no update available instead of a
hard failure, and stop swallowing updater capability/download errors in the
desktop bridge so About/sidebar can show actionable messages.

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* docs: credit Linux AppImage contributors in changelog

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

---------

Co-authored-by: jibanez-staticduo <staticduo@gmail.com>
Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/ui/src/lib/settings/search.ts

@@ -24,6 +24,8 @@ interface SettingsSearchAvailabilityContext extends SettingsRuntimeContext {
   isMac: boolean;
   // Windows desktop shell — for controls that only render on win32.
   isWindows: boolean;
+  // Linux desktop shell — for controls that only render on linux.
+  isLinux: boolean;
 }
 
 const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
@@ -385,7 +387,7 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     page: 'general',
     titleKey: 'settings.openchamber.desktopNetwork.field.launchAtLogin',
     descriptionKey: 'settings.openchamber.desktopNetwork.field.launchAtLoginDescription',
-    keywords: ['desktop', 'startup', 'login'],
+    keywords: ['desktop', 'startup', 'login', 'launch', 'background', 'autostart'],
     isAvailable: (ctx) => ctx.isDesktopLocalOrigin,
   },
   {
@@ -409,8 +411,8 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     page: 'general',
     titleKey: 'settings.openchamber.desktopNetwork.field.minimizeToTray',
     descriptionKey: 'settings.openchamber.desktopNetwork.field.minimizeToTrayDescription',
-    keywords: ['desktop', 'tray', 'system tray', 'minimize', 'close', 'background', 'windows'],
-    isAvailable: (ctx) => ctx.isDesktopLocalOrigin && ctx.isWindows,
+    keywords: ['desktop', 'tray', 'system tray', 'minimize', 'close', 'background', 'windows', 'linux'],
+    isAvailable: (ctx) => ctx.isDesktopLocalOrigin && (ctx.isWindows || ctx.isLinux),
   },
   {
     id: 'sessions.desktop-keep-awake',