test(client): 用例名统一为 should_<期望>_when_<条件>（155/155）

为什么：红线第 8 条门禁立即生效，要求 Flutter 测试命名合规；此前 155 条用例名是英文自然语言
或中文描述，合规数 0/155，属存量欠账，按"先补齐再上新功能"在本批处理。

- 25 个测试文件、155 条用例改名，按「文件 + 旧名」精确定位，每条断言命中恰好 1 次才替换
- 只改名字字面量：改动行 155 删 + 155 增，无一行不含字符串字面量（断言与用例体零改动）
- 门禁：dart analyze lib test = No issues found；flutter test = 155 全过

test/config/locale_controller_test.dart

@@ -11,7 +11,7 @@ void main() {
         InMemorySharedPreferencesAsync.empty();
   });
 
-  test('no stored choice keeps the device locale', () async {
+  test('should_keep_device_locale_when_no_choice_is_stored', () async {
     final controller = LocaleController();
     var notifications = 0;
     controller.addListener(() => notifications++);
@@ -22,7 +22,7 @@ void main() {
     expect(notifications, 1);
   });
 
-  test('a chosen language survives a restart', () async {
+  test('should_restore_chosen_language_when_app_restarts', () async {
     final first = LocaleController();
     await first.select('zh');
     expect(first.locale, const Locale('zh'));
@@ -32,7 +32,7 @@ void main() {
     expect(reopened.locale, const Locale('zh'));
   });
 
-  test('selecting english clears a stored chinese preference', () async {
+  test('should_clear_stored_chinese_preference_when_english_is_selected', () async {
     await LocaleController().select('zh');
 
     final reopened = LocaleController();
@@ -44,7 +44,7 @@ void main() {
     expect(third.locale, const Locale('en'));
   });
 
-  test('an unsupported code clears the locale instead of throwing', () async {
+  test('should_clear_locale_when_code_is_unsupported', () async {
     final controller = LocaleController();
     await controller.select('zh');
     expect(controller.locale, const Locale('zh'));
@@ -54,7 +54,7 @@ void main() {
     expect(controller.locale, isNull);
   });
 
-  test('an unsupported stored code resolves to the device locale', () async {
+  test('should_resolve_to_device_locale_when_stored_code_is_unsupported', () async {
     await SharedPreferencesAsync().setString('ui.locale', 'fr');
 
     final controller = LocaleController();
@@ -63,7 +63,7 @@ void main() {
     expect(controller.locale, isNull);
   });
 
-  test('a broken preference store never breaks load or select', () async {
+  test('should_survive_load_and_select_when_preference_store_is_broken', () async {
     SharedPreferencesAsyncPlatform.instance = _BrokenPreferences();
     final controller = LocaleController();