feat(mobile): sign-in, tabs, search, collection and background player (M5)

- expo-router app in src/app: connect (server check, recent servers),
  login, mandatory credential / password change, tabs Home / Search /
  Collection / Profile, album and artist pages, full-screen player
- AuthSession per server with the refresh token in expo-secure-store
  (Android Keystore); language from the profile
- player on react-native-track-player: ExoPlayer queue with a
  notification and lock-screen controls via a playback service, 500 MB
  stream cache, quality by network (Wi-Fi high, cellular medium),
  play events with played time, reactions, playback state restore and
  the endless My Wave with feedback
- home: pulsing wave circle driven by BPM / energy in the cover
  palette, activity and mood chips that switch the wave on the fly
- New Architecture is off until react-native-track-player supports it;
  the release build runs codegen only when it is on; query-string is a
  direct dependency because expo-router 5.1 imports it undeclared

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

apps/mobile/app.config.ts

@@ -12,7 +12,9 @@ export default ({ config }: ConfigContext): ExpoConfig => ({
   version,
   orientation: 'portrait',
   userInterfaceStyle: 'automatic',
-  newArchEnabled: true,
+  // react-native-track-player 4 не поддерживает New Architecture (React Native Directory) — фоновое
+  // воспроизведение и уведомление важнее; вернём, когда плеер её поддержит (docs/mobile.md).
+  newArchEnabled: false,
   backgroundColor: '#05070D',
   android: {
     package: 'app.pipu.music',
@@ -23,9 +25,13 @@ export default ({ config }: ConfigContext): ExpoConfig => ({
   },
   platforms: ['android'],
   plugins: [
+    // Маршруты — файлы в src/app (docs/mobile.md).
+    ['expo-router', { root: './src/app' }],
+    'expo-secure-store',
     // Сервер часто живёт в домашней сети без TLS (http://192.168.1.10:8080), а release-сборка
     // Android по умолчанию запрещает незашифрованный HTTP.
     ['expo-build-properties', { android: { usesCleartextTraffic: true } }],
   ],
   extra: { versionCode },
+  experiments: { typedRoutes: false },
 });