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/ranges/gtr.js

@@ -0,0 +1,6 @@
+'use strict'
+
+// Determine if version is greater than all the versions possible in the range.
+const outside = require('./outside')
+const gtr = (version, range, options) => outside(version, range, '>', options)
+module.exports = gtr