feat(voice): add real-time voice room with LiveKit

- LiveKit WebRTC SFU container in docker-compose
- Voice token microservice (Node.js + Express)
- VoiceRoom page with member grid and controls
- useVoiceRoom composable for LiveKit connection
- Voice entry button in TeamSessionPanel
- Nginx proxy for voice-token service API

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/voice-token-service/Dockerfile

@@ -0,0 +1,7 @@
+FROM node:20-alpine
+WORKDIR /app
+COPY package.json package-lock.json* ./
+RUN npm install --production
+COPY server.js .
+EXPOSE 7882
+CMD ["npm", "start"]