fix: Audio preloading to prevent stuttering, remove trailing dots for XTTS

- Preload next audio while current plays (eliminates gap between sentences)
- Remove trailing dots from sentences (XTTS reads them aloud)
- stopPlayback cleans up preloaded audio

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

android/src/services/audio.ts

@@ -58,6 +58,8 @@ class AudioService {
   // Audio-Queue fuer sequentielle TTS-Wiedergabe
   private audioQueue: string[] = [];
   private isPlaying: boolean = false;
+  private preloadedSound: Sound | null = null;
+  private preloadedPath: string = '';
 
   // VAD State
   private vadEnabled: boolean = false;
@@ -220,35 +222,62 @@ class AudioService {
     }
 
     this.isPlaying = true;
-    const base64Data = this.audioQueue.shift()!;
 
-    try {
-      const tmpPath = `${RNFS.CachesDirectoryPath}/aria_tts_${Date.now()}.wav`;
-      await RNFS.writeFile(tmpPath, base64Data, 'base64');
+    // Preloaded Sound verwenden wenn verfuegbar, sonst neu laden
+    let sound: Sound;
+    let soundPath: string;
 
-      this.currentSound = new Sound(tmpPath, '', (error) => {
-        if (error) {
-          console.error('[Audio] Fehler beim Laden:', error);
-          RNFS.unlink(tmpPath).catch(() => {});
-          this._playNext();
-          return;
-        }
-        this.currentSound?.play((success) => {
-          if (success) {
-            console.log('[Audio] Wiedergabe abgeschlossen');
-          } else {
-            console.warn('[Audio] Wiedergabe fehlgeschlagen');
-          }
-          this.currentSound?.release();
-          this.currentSound = null;
-          RNFS.unlink(tmpPath).catch(() => {});
-          // Naechstes Audio abspielen
-          this._playNext();
+    if (this.preloadedSound) {
+      sound = this.preloadedSound;
+      soundPath = this.preloadedPath;
+      this.preloadedSound = null;
+      this.preloadedPath = '';
+      // Daten aus Queue entfernen (wurde schon preloaded)
+      this.audioQueue.shift();
+    } else {
+      const base64Data = this.audioQueue.shift()!;
+      try {
+        soundPath = `${RNFS.CachesDirectoryPath}/aria_tts_${Date.now()}.wav`;
+        await RNFS.writeFile(soundPath, base64Data, 'base64');
+        sound = await new Promise<Sound>((resolve, reject) => {
+          const s = new Sound(soundPath, '', (err) => err ? reject(err) : resolve(s));
         });
-      });
-    } catch (err) {
-      console.error('[Audio] Wiedergabefehler:', err);
+      } catch (err) {
+        console.error('[Audio] Laden fehlgeschlagen:', err);
+        this._playNext();
+        return;
+      }
+    }
+
+    this.currentSound = sound;
+
+    // Naechstes Audio schon vorbereiten waehrend dieses abspielt
+    this._preloadNext();
+
+    sound.play((success) => {
+      if (!success) console.warn('[Audio] Wiedergabe fehlgeschlagen');
+      sound.release();
+      this.currentSound = null;
+      RNFS.unlink(soundPath).catch(() => {});
       this._playNext();
+    });
+  }
+
+  /** Naechstes Audio im Hintergrund vorladen (verhindert Stottern) */
+  private async _preloadNext(): Promise<void> {
+    if (this.audioQueue.length === 0 || this.preloadedSound) return;
+
+    const base64Data = this.audioQueue[0]; // Nicht shift — bleibt in Queue
+    try {
+      const tmpPath = `${RNFS.CachesDirectoryPath}/aria_tts_pre_${Date.now()}.wav`;
+      await RNFS.writeFile(tmpPath, base64Data, 'base64');
+      this.preloadedSound = await new Promise<Sound>((resolve, reject) => {
+        const s = new Sound(tmpPath, '', (err) => err ? reject(err) : resolve(s));
+      });
+      this.preloadedPath = tmpPath;
+    } catch {
+      this.preloadedSound = null;
+      this.preloadedPath = '';
     }
   }
 
@@ -261,6 +290,12 @@ class AudioService {
       this.currentSound.release();
       this.currentSound = null;
     }
+    if (this.preloadedSound) {
+      this.preloadedSound.release();
+      this.preloadedSound = null;
+      if (this.preloadedPath) RNFS.unlink(this.preloadedPath).catch(() => {});
+      this.preloadedPath = '';
+    }
   }
 
   // --- Status & Callbacks ---

xtts/bridge.js

@@ -101,7 +101,10 @@ async function handleTTSRequest(payload) {
   const cleanText = text.replace(/\*\*([^*]+)\*\*/g, "$1").trim();
 
   // Text in Saetze aufteilen (sequentiell rendern fuer korrekte Reihenfolge)
-  const sentences = cleanText.split(/(?<=[.!?])\s+/).map(s => s.trim()).filter(s => s.length > 0);
+  const sentences = cleanText.split(/(?<=[.!?])\s+/)
+    .map(s => s.trim())
+    .filter(s => s.length > 0)
+    .map(s => s.replace(/[.]+$/, '')); // Punkt am Ende entfernen (XTTS liest ihn sonst vor)
   if (sentences.length === 0) return;
 
   log(`TTS-Request: "${cleanText.slice(0, 60)}..." (${sentences.length} Saetze, voice: ${voice || "default"}, lang: ${language || "de"})`);