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/tailwindcss/resolveConfig.js

@@ -0,0 +1,2 @@
+let resolveConfig = require('./lib/public/resolve-config')
+module.exports = (resolveConfig.__esModule ? resolveConfig : { default: resolveConfig }).default