YouTube/Twitch live chat backend WebSocket proxy

- YouTube chat polling via liveBroadcasts + liveChat/messages APIs
- Twitch IRC WebSocket client with IRCv3 tag parsing
- ChatManager orchestrator with token refresh, retry logic
- WebSocket endpoint at /chat/ws with JWT auth
- Added chat:read, chat:edit to Twitch OAuth scopes

package.json

@@ -19,6 +19,7 @@
     "@fastify/cookie": "^11.0.1",
     "@fastify/cors": "^10.0.1",
     "@fastify/rate-limit": "^10.2.1",
+    "@fastify/websocket": "^11.2.0",
     "@prisma/client": "^6.4.1",
     "fastify": "^5.2.1",
     "fastify-plugin": "^5.0.1",
@@ -27,9 +28,10 @@
   },
   "devDependencies": {
     "@types/node": "^22.13.4",
+    "@types/ws": "^8.18.1",
     "prisma": "^6.4.1",
     "tsx": "^4.19.3",
     "typescript": "^5.7.3",
     "vitest": "^3.0.5"
   }
-}
+}