feat(app): remember window size/position across restarts (window-state plugin)

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

app/src-tauri/src/lib.rs

@@ -5,6 +5,8 @@ use tauri::Manager;
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     tauri::Builder::default()
+        // Persist + restore the window's size, position and maximized state across restarts.
+        .plugin(tauri_plugin_window_state::Builder::default().build())
         .plugin(tauri_plugin_notification::init())
         .setup(|app| {
             let handle = app.handle().clone();