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/eslint/messages/print-config-with-directory-path.js

@@ -0,0 +1,8 @@
+"use strict";
+
+module.exports = function() {
+    return `
+The '--print-config' CLI option requires a path to a source code file rather than a directory.
+See also: https://eslint.org/docs/latest/use/command-line-interface#--print-config
+`.trimStart();
+};