feat(desktop): add offline cache and verified app updates

Clean release notes in Android and desktop update dialogs. Persist downloaded audio and offline playback events per server and user; add desktop update checks, checksum verification and installer launch.

apps/web/src/app/router.tsx

@@ -33,6 +33,7 @@ import { SettingsPage } from '../pages/SettingsPage';
 import { SetupPage } from '../pages/SetupPage';
 import { AppShell } from '../widgets/AppShell';
 import { RouteError } from '../widgets/RouteError';
+import { DesktopDownloadsPage } from '../features/desktop/DesktopFeatures';
 
 export interface RouterContext {
   session: AuthSession;
@@ -147,6 +148,9 @@ const homeRoute = createRoute({ getParentRoute: () => appRoute, path: '/', compo
 const trackRoute = createRoute({ getParentRoute: () => appRoute, path: '/track/$id', component: () => <TrackPage key={trackRoute.useParams().id} id={trackRoute.useParams().id} /> });
 const sharedPlaylistRoute = createRoute({ getParentRoute: () => appRoute, path: '/shared/playlist/$shareId', component: () => <PlaylistPage key={sharedPlaylistRoute.useParams().shareId} id={sharedPlaylistRoute.useParams().shareId} shared /> });
 const playlistsRoute = createRoute({ getParentRoute: () => appRoute, path: '/collection/playlists', component: PlaylistsPage });
+const downloadsRoute = createRoute({ getParentRoute: () => appRoute, path: '/collection/downloads', component: DesktopDownloadsPage,
+  beforeLoad: ({ context }) => { if (!context.desktop) throw redirect({ to: '/settings' }); },
+});
 const playlistRoute = createRoute({ getParentRoute: () => appRoute, path: '/playlist/$id', component: () => <PlaylistPage id={playlistRoute.useParams().id} /> });
 
 const settingsRoute = createRoute({ getParentRoute: () => appRoute, path: '/settings', component: SettingsPage });
@@ -281,6 +285,7 @@ const routeTree = rootRoute.addChildren([
     homeRoute,
     trackRoute,
     playlistsRoute,
+    downloadsRoute,
     sharedPlaylistRoute,
     playlistRoute,
     settingsRoute,