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

node-network-app/node_modules/nanoid/async/package.json

@@ -0,0 +1,12 @@
+{
+  "type": "module",
+  "main": "index.cjs",
+  "module": "index.js",
+  "react-native": {
+    "./index.js": "./index.native.js"
+  },
+  "browser": {
+    "./index.js": "./index.browser.js",
+    "./index.cjs": "./index.browser.cjs"
+  }
+}