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>

docker-compose.backend.yml

@@ -33,6 +33,22 @@ services:
     networks:
       - gamegroup-net
 
+  voice-token:
+    build:
+      context: ./backend/voice-token-service
+    container_name: gamegroup-voice-token
+    ports:
+      - "7882:7882"
+    environment:
+      - LIVEKIT_API_KEY=APIyxZGQjM2
+      - LIVEKIT_API_SECRET=secretNmU4ZDU3YjA0OWIxNDM4YjhlNWY3YTFjZGUzOWRi
+      - PB_URL=http://gamegroup-pb:8090
+    restart: unless-stopped
+    depends_on:
+      - pocketbase
+    networks:
+      - gamegroup-net
+
 networks:
   gamegroup-net:
     driver: bridge