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/@babel/helper-module-imports/README.md

@@ -0,0 +1,19 @@
+# @babel/helper-module-imports
+
+> Babel helper functions for inserting module loads
+
+See our website [@babel/helper-module-imports](https://babeljs.io/docs/babel-helper-module-imports) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save @babel/helper-module-imports
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/helper-module-imports
+```