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/plugin.d.ts

@@ -0,0 +1,11 @@
+import type { Config, PluginCreator } from './types/config'
+type Plugin = {
+  withOptions<T>(
+    plugin: (options: T) => PluginCreator,
+    config?: (options: T) => Partial<Config>
+  ): { (options: T): { handler: PluginCreator; config?: Partial<Config> }; __isOptionsFunction: true }
+  (plugin: PluginCreator, config?: Partial<Config>): { handler: PluginCreator; config?: Partial<Config> }
+}
+
+declare const plugin: Plugin
+export = plugin