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/is-binary-path/index.js

@@ -0,0 +1,7 @@
+'use strict';
+const path = require('path');
+const binaryExtensions = require('binary-extensions');
+
+const extensions = new Set(binaryExtensions);
+
+module.exports = filePath => extensions.has(path.extname(filePath).slice(1).toLowerCase());