- Add VoiceTransmitter class to handle PCM audio from backend/browser to Discord
- Implement voice:transmit:start and voice:transmit:stop command handlers
- Upsample 24kHz mono PCM to 48kHz stereo for Discord compatibility
- Encode PCM to Opus and stream via browser-bridge player owner
- Subscribe to Redis channel backend:voice:transmit for real-time PCM data
Features:
- Backend can send PCM audio (24kHz mono s16le base64) via Redis
- Automatic upsampling and encoding to Discord-compatible format
- Clean start/stop lifecycle with resource cleanup
This completes the bidirectional voice streaming:
- Listen: Discord → Backend (already working via voicePcmData broadcast)
- Transmit: Backend → Discord (now implemented)
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
