feat: XTTS v2 integration, auto-update system, TTS engine abstraction

- XTTS v2: Docker setup for Gaming-PC (GPU), bridge via RVS relay
- XTTS: Voice cloning UI in Diagnostic (multi-file upload)
- XTTS: Engine selectable (Piper local vs XTTS remote) with fallback
- Auto-Update: RVS serves APK over WebSocket (no HTTP needed)
- Auto-Update: App checks version on start, prompts install
- Auto-Update: release.sh copies APK to RVS via scp
- Bridge: TTS engine abstraction (piper/xtts), config persistent
- Bridge: xtts_response handler, tts_request on-demand
- Diagnostic: TTS engine dropdown, XTTS voice panel, voice cloning
- App: Play button on ARIA messages, chat search, update service
- Wake word: Disabled LiveAudioStream (crash fix), Phase 1 placeholder
- Watchdog: Container restart after 8min stuck
- Chat backup: on-the-fly to /shared/config/chat_backup.jsonl

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

android/src/screens/ChatScreen.tsx

@@ -23,6 +23,7 @@ import RNFS from 'react-native-fs';
 import rvs, { RVSMessage, ConnectionState } from '../services/rvs';
 import audioService from '../services/audio';
 import wakeWordService from '../services/wakeword';
+import updateService from '../services/updater';
 import VoiceButton from '../components/VoiceButton';
 import FileUpload, { FileData } from '../components/FileUpload';
 import CameraUpload, { PhotoData } from '../components/CameraUpload';
@@ -262,6 +263,16 @@ const ChatScreen: React.FC = () => {
     };
   }, []);
 
+  // Auto-Update: Bei App-Start pruefen
+  useEffect(() => {
+    const unsubUpdate = updateService.onUpdateAvailable((info) => {
+      updateService.promptUpdate(info);
+    });
+    // Nach 5s pruefen (RVS muss erst verbunden sein)
+    const timer = setTimeout(() => updateService.checkForUpdate(), 5000);
+    return () => { unsubUpdate(); clearTimeout(timer); };
+  }, []);
+
   // Wake Word: "ARIA" Erkennung → Auto-Aufnahme starten
   useEffect(() => {
     const unsubWake = wakeWordService.onWakeWord(async () => {