feat: select directory to save last book cover image (#2521)

apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/src/lib.rs

@@ -57,6 +57,7 @@ pub fn init<R: Runtime>() -> TauriPlugin<R> {
             commands::set_screen_brightness,
             commands::get_external_sdcard_path,
             commands::open_external_url,
+            commands::select_directory,
             commands::request_manage_storage_permission,
         ])
         .setup(|app, api| {