feat: Android download page, analysis retry and a collapsible search

- /android is a public page with the latest APK, the server address to copy
  and three install steps; linked from the sign-in screen and the profile menu
- failed audio analysis can be retried from the library page, which also shows
  the most common error; the analyzer no longer burns attempts on files that
  are missing because the disk is not mounted
- the top bar search folds into a round button and slides open on click, "/"
  or Ctrl+K

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/app/router.tsx

@@ -21,6 +21,7 @@ import { AlbumPage } from '../pages/AlbumPage';
 import { ArtistPage } from '../pages/ArtistPage';
 import { CollectionPage } from '../pages/CollectionPage';
 import { HomePage } from '../pages/HomePage';
+import { AppDownloadPage } from '../pages/AppDownloadPage';
 import { LoginPage } from '../pages/LoginPage';
 import { SearchPage, type SearchType } from '../pages/SearchPage';
 import { SettingsPage } from '../pages/SettingsPage';
@@ -59,6 +60,9 @@ const rootRoute = createRootRouteWithContext<RouterContext>()({
   errorComponent: RouteError,
 });
 
+// Публичная: ссылку на приложение отправляют тем, у кого ещё нет аккаунта на этом устройстве.
+const androidAppRoute = createRoute({ getParentRoute: () => rootRoute, path: '/android', component: AppDownloadPage });
+
 const loginRoute = createRoute({
   getParentRoute: () => rootRoute,
   path: '/login',
@@ -233,6 +237,7 @@ const adminSettingsRoute = createRoute({
 });
 
 const routeTree = rootRoute.addChildren([
+  androidAppRoute,
   loginRoute,
   setupAdminRoute,
   setupPasswordRoute,