feat(app): Event Center, native notifications, auto-unread, state wiring in App

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/src-tauri/src/lib.rs

@@ -5,6 +5,7 @@ use tauri::Manager;
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     tauri::Builder::default()
+        .plugin(tauri_plugin_notification::init())
         .setup(|app| {
             let handle = app.handle().clone();
             // Connect the bridge on a tokio runtime, then manage it.