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_modules/resolve/test/resolver/nested_symlinks/mylib/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "mylib",
+  "version": "0.0.0",
+  "description": "",
+  "private": true,
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "buffer": "*"
+  }
+}