fix: i18n

ui/flutter/lib/pages/app/app_controller.dart

@@ -147,7 +147,10 @@ class AppController extends GetxController {
       extra.themeMode = ThemeMode.system.name;
     }
     if (extra.locale.isEmpty) {
-      extra.locale = getLocaleKey(ui.window.locale);
+      final systemLocale = getLocaleKey(ui.window.locale);
+      extra.locale = messages.keys.containsKey(systemLocale)
+          ? systemLocale
+          : getLocaleKey(fallbackLocale);
     }
     if (extra.bt.trackerSubscribeUrls.isEmpty) {
       // default select all tracker subscribe urls
@@ -159,6 +162,10 @@ class AppController extends GetxController {
           '${await ExternalPath.getExternalStoragePublicDirectory(ExternalPath.DIRECTORY_DOWNLOADS)}/com.gopeed';
       return;
     }
+    if (Util.isIOS()) {
+      config.downloadDir = 'Documents';
+      return;
+    }
 
     if (config.downloadDir.isEmpty) {
       if (Util.isWeb()) {

ui/flutter/lib/pages/setting/setting_view.dart

@@ -231,14 +231,14 @@ class SettingView extends GetView<SettingController> {
 
     // about config items start
     buildHomepage() => ListTile(
-          title: Text('主页'.tr),
+          title: Text('setting.homepage'.tr),
           subtitle: const Text('https://github.com/monkeyWie/gopeed'),
           onTap: () {
             launchUrl(Uri.parse('https://github.com/monkeyWie/gopeed'));
           },
         );
     buildVersion() => ListTile(
-          title: Text('版本'.tr),
+          title: Text('setting.version'.tr),
           subtitle: Text(packageInfo.version),
         );