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/@nodelib/fs.walk/out/providers/async.d.ts

@@ -0,0 +1,12 @@
+import AsyncReader from '../readers/async';
+import type Settings from '../settings';
+import type { Entry, Errno } from '../types';
+export declare type AsyncCallback = (error: Errno, entries: Entry[]) => void;
+export default class AsyncProvider {
+    private readonly _root;
+    private readonly _settings;
+    protected readonly _reader: AsyncReader;
+    private readonly _storage;
+    constructor(_root: string, _settings: Settings);
+    read(callback: AsyncCallback): void;
+}