feat(desktop): 添加悬浮球 Quick Ask 功能

- 实现浅灰色玻璃拟态悬浮球，带机器人头图标
- 支持点击展开对话框，淡入淡出动画
- 支持窗口拖拽，区分点击和拖拽操作
- macOS 透明窗口支持 (macOSPrivateApi)
- 悬浮球 hover 放大效果，不溢出窗口
- 添加系统托盘 Toggle Quick Ask 菜单

packages/desktop/src-tauri/src/lib.rs

@@ -21,16 +21,22 @@ pub fn run() {
             commands::open_directory_dialog,
             commands::read_local_file,
             commands::list_directory,
+            commands::toggle_floating_window,
+            commands::show_floating_window,
+            commands::hide_floating_window,
+            commands::show_main_window,
+            commands::set_floating_window_size,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");
 }
 
 fn setup_tray<R: Runtime>(app: &tauri::App<R>) -> Result<(), Box<dyn std::error::Error>> {
-    let show_item = MenuItem::with_id(app, "show", "Show Window", true, None::<&str>)?;
+    let show_item = MenuItem::with_id(app, "show", "Show Main Window", true, None::<&str>)?;
+    let floating_item = MenuItem::with_id(app, "floating", "Toggle Quick Ask", true, None::<&str>)?;
     let quit_item = MenuItem::with_id(app, "quit", "Quit", true, None::<&str>)?;
 
-    let menu = Menu::with_items(app, &[&show_item, &quit_item])?;
+    let menu = Menu::with_items(app, &[&show_item, &floating_item, &quit_item])?;
 
     let _tray = TrayIconBuilder::new()
         .menu(&menu)
@@ -42,6 +48,16 @@ fn setup_tray<R: Runtime>(app: &tauri::App<R>) -> Result<(), Box<dyn std::error:
                     let _ = window.set_focus();
                 }
             }
+            "floating" => {
+                if let Some(window) = app.get_webview_window("floating") {
+                    if window.is_visible().unwrap_or(false) {
+                        let _ = window.hide();
+                    } else {
+                        let _ = window.show();
+                        let _ = window.set_focus();
+                    }
+                }
+            }
             "quit" => {
                 app.exit(0);
             }