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/formatting/localized_content_test.dart

@@ -17,7 +17,7 @@ void main() {
   final en = AppLocalizationsEn();
   final zh = AppLocalizationsZh();
 
-  test('each seeded drama maps onto its own localized copy', () {
+  test('should_map_each_seeded_drama_to_its_own_localized_copy_when_looked_up', () {
     final signal = _drama(id: 'the-signal-demo');
     final city = _drama(id: 'city-lights-demo');
     final vengeance = _drama(id: 'vengeance-demo');
@@ -31,7 +31,7 @@ void main() {
     expect(localizedDramaSynopsis(en, vengeance), en.dramaVengeanceSynopsis);
   });
 
-  test('the mapping does not collapse two dramas onto one entry', () {
+  test('should_keep_two_dramas_apart_when_localized_copy_is_mapped', () {
     final titles = {
       localizedDramaTitle(en, _drama(id: 'the-signal-demo')),
       localizedDramaTitle(en, _drama(id: 'city-lights-demo')),
@@ -47,7 +47,7 @@ void main() {
     expect(synopses, hasLength(3));
   });
 
-  test('localized copy is translated rather than reused verbatim', () {
+  test('should_translate_localized_copy_when_content_is_looked_up', () {
     final signal = _drama(id: 'the-signal-demo');
 
     expect(localizedDramaTitle(zh, signal), zh.dramaSignalTitle);
@@ -55,7 +55,7 @@ void main() {
     expect(localizedDramaTitle(zh, signal), isNot(en.dramaSignalTitle));
   });
 
-  test('an unknown drama keeps the catalog text in every locale', () {
+  test('should_keep_catalog_text_in_every_locale_when_drama_is_unknown', () {
     final custom = _drama(
       id: 'custom-demo',
       title: 'Custom Title',
@@ -68,7 +68,7 @@ void main() {
     expect(localizedDramaSynopsis(zh, custom), 'Custom synopsis');
   });
 
-  test('the raw catalog text is ignored for a seeded drama', () {
+  test('should_ignore_raw_catalog_text_when_drama_is_seeded', () {
     final signal = _drama(
       id: 'the-signal-demo',
       title: 'stale title',
@@ -79,14 +79,14 @@ void main() {
     expect(localizedDramaSynopsis(en, signal), isNot('stale synopsis'));
   });
 
-  test('episodes one to four use named titles', () {
+  test('should_use_named_titles_when_episode_number_is_one_to_four', () {
     expect(localizedEpisodeTitle(en, 1), en.episodeOneTitle);
     expect(localizedEpisodeTitle(en, 2), en.episodeTwoTitle);
     expect(localizedEpisodeTitle(en, 3), en.episodeThreeTitle);
     expect(localizedEpisodeTitle(en, 4), en.episodeFourTitle);
   });
 
-  test('later episodes fall back to a numbered label', () {
+  test('should_fall_back_to_numbered_label_when_episode_number_is_later', () {
     for (final number in <int>[5, 12, 100]) {
       expect(localizedEpisodeTitle(en, number), en.episodeLabel(number));
       expect(localizedEpisodeTitle(en, number), contains('$number'));