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/@nodelib/fs.walk/out/readers/common.d.ts

@@ -0,0 +1,7 @@
+import type { FilterFunction } from '../settings';
+import type Settings from '../settings';
+import type { Errno } from '../types';
+export declare function isFatalError(settings: Settings, error: Errno): boolean;
+export declare function isAppliedFilter<T>(filter: FilterFunction<T> | null, value: T): boolean;
+export declare function replacePathSegmentSeparator(filepath: string, separator: string): string;
+export declare function joinPathSegments(a: string, b: string, separator: string): string;