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/callsites/index.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const callsites = () => {
+	const _prepareStackTrace = Error.prepareStackTrace;
+	Error.prepareStackTrace = (_, stack) => stack;
+	const stack = new Error().stack.slice(1);
+	Error.prepareStackTrace = _prepareStackTrace;
+	return stack;
+};
+
+module.exports = callsites;
+// TODO: Remove this for the next major release
+module.exports.default = callsites;