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/semver/functions/major.js

@@ -0,0 +1,5 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const major = (a, loose) => new SemVer(a, loose).major
+module.exports = major