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/example/sync.js

@@ -0,0 +1,3 @@
+var resolve = require('../');
+var res = resolve.sync('tap', { basedir: __dirname });
+console.log(res);