feat(flutter): 应用克莱因蓝主题与印尼语适配

lib/core/config/locale_controller.dart

@@ -3,6 +3,19 @@
 import 'package:flutter/widgets.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
+/// Resolves the selected or system language to one of the supported app locales.
+///
+/// Indonesian is the launch-market fallback when a device uses an unsupported
+/// language. The legacy `in` code is treated as Indonesian as well.
+Locale resolveAppLocale(Locale? selected, Locale? deviceLocale) {
+  final code = (selected ?? deviceLocale)?.languageCode;
+  return switch (code) {
+    'zh' => const Locale('zh'),
+    'en' => const Locale('en'),
+    _ => const Locale('id'),
+  };
+}
+
 class LocaleController extends ChangeNotifier {
   LocaleController({SharedPreferencesAsync? preferences})
     : _preferences = preferences ?? SharedPreferencesAsync();
@@ -17,6 +30,7 @@ class LocaleController extends ChangeNotifier {
       _locale = switch (code) {
         'en' => const Locale('en'),
         'zh' => const Locale('zh'),
+        'id' => const Locale('id'),
         _ => null,
       };
       notifyListeners();
@@ -29,6 +43,7 @@ class LocaleController extends ChangeNotifier {
     _locale = switch (code) {
       'en' => const Locale('en'),
       'zh' => const Locale('zh'),
+      'id' => const Locale('id'),
       _ => null,
     };
     notifyListeners();