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/fast-glob/out/utils/string.js

@@ -0,0 +1,11 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.isEmpty = exports.isString = void 0;
+function isString(input) {
+    return typeof input === 'string';
+}
+exports.isString = isString;
+function isEmpty(input) {
+    return input === '';
+}
+exports.isEmpty = isEmpty;