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/index.js

@@ -0,0 +1,6 @@
+var async = require('./lib/async');
+async.core = require('./lib/core');
+async.isCore = require('./lib/is-core');
+async.sync = require('./lib/sync');
+
+module.exports = async;