feat: Add presence heartbeat for Matrix online status

- matrix-gateway: POST /internal/matrix/presence/online endpoint
- usePresenceHeartbeat hook with activity tracking
- Auto away after 5 min inactivity
- Offline on page close/visibility change
- Integrated in MatrixChatRoom component

tsconfig.node.json

@@ -4,8 +4,9 @@
     "skipLibCheck": true,
     "module": "ESNext",
     "moduleResolution": "bundler",
-    "allowSyntheticDefaultImports": true
+    "allowSyntheticDefaultImports": true,
+    "lib": ["ESNext"]
   },
-  "include": ["vite.config.ts"]
+  "include": ["vite.config.ts", "scripts/*.ts"]
 }