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/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "gamegroup-voice-token",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "start": "node server.js"
+  },
+  "dependencies": {
+    "livekit-server-sdk": "^2.0",
+    "express": "^4.21"
+  }
+}