The Android app updates itself from our Gitea releases; feed cards fade in instead of bouncing

- API: GET /app/android/latest reads the latest Gitea release (ANDROID_RELEASES_URL, optional token for a
  private repo) with the APK's SHA-256 from SHA256SUMS; GET /app/android/apk/:name streams that APK.
- App (modules/updater): downloads in the background, checks the SHA-256, and installs through
  PackageInstaller: quietly once when leaving the app (Android 12+), otherwise from the feed banner or
  Settings > App version. F-Droid builds leave it out and drop the install permissions.
- CI: the release notes come from the fastlane changelog; the app shows the part above ---.
- Settings: Create-account and Link Spotify buttons for Last.fm and ListenBrainz.

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

apps/mobile/app.config.ts

@@ -21,6 +21,11 @@ export default ({ config }: ConfigContext): ExpoConfig => {
   return {
     ...(config as ExpoConfig),
     extra: { ...config.extra, foss },
-    plugins: [...plugins, ['expo-build-properties', { android: { usesCleartextTraffic: localHttp } }] satisfies Plugin],
+    plugins: [
+      ...plugins,
+      ['expo-build-properties', { android: { usesCleartextTraffic: localHttp } }] satisfies Plugin,
+      // F-Droid delivers updates itself; only our own builds install them (modules/updater).
+      ...(foss ? ['./plugins/withoutSelfUpdate'] : []),
+    ],
   };
 };