feat: add audios table and ElevenLabs TTS endpoint

- New audios table with voice params, S3 link, alignment JSON
- POST /api/audios/generate calls ElevenLabs with-timestamps, uploads to S3
- GET/PATCH/DELETE /api/audios endpoints
- Requires ELEVENLABS_API_KEY env var

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/index.js

@@ -40,6 +40,7 @@ app.use('/api/languages', auth, require('./routes/languages'));
 app.use('/api/user-names', auth, require('./routes/user-names'));
 app.use('/api/users-public', auth, require('./routes/users-public'));
 app.use('/api/users', auth, require('./routes/users'));
+app.use('/api/audios', auth, require('./routes/audios'));
 app.use('/api/claude', auth, require('./routes/claude'));
 
 // 404