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/is-binary-path/index.d.ts

@@ -0,0 +1,17 @@
+/**
+Check if a file path is a binary file.
+
+@example
+```
+import isBinaryPath = require('is-binary-path');
+
+isBinaryPath('source/unicorn.png');
+//=> true
+
+isBinaryPath('source/unicorn.txt');
+//=> false
+```
+*/
+declare function isBinaryPath(filePath: string): boolean;
+
+export = isBinaryPath;