FEAT: 精听首次点「听不太懂」弹窗说明自动收藏，弹窗内可直接开关

- 新增持久化标记 unclearReminderShown（仅本机），首次点击先弹窗，确认后进入讲解
- 弹窗内开关即时写回「听不懂时自动收藏」设置，并提示可在学习设置中修改
- 修正上一提交的英文文案为 Unclear / saved 用语
- 命名统一：收藏用 save，「听不太懂」用 unclear（持久化字符串值保持不变）
- 补充 provider、弹窗、精听页测试；修复测试 fake 未实现新方法导致的编译失败

Author: echo-loop

TASKS.md

@@ -3,6 +3,7 @@
 > 当前待办与本次完成记录；此前完成任务已归档，详见 [2026-10-29 归档](./docs/tasks-archive/tasks-2026-10-29-completed.md)、[2026-09-29 归档](./docs/tasks-archive/tasks-2026-09-29-completed.md)。
 
 ## 本次完成
+- [x] 首次点「听不太懂」弹出自动收藏说明（一次性）：精听中第一次点击「听不太懂」，进入讲解页前弹窗说明该操作会自动收藏句子，弹窗内可直接切换「听不懂时自动收藏」开关（即时生效），并提示可在「学习设置」随时修改。已提示标记 `learning_cant_understand_auto_favorite_reminder_shown` 存 SP（仅本机，老用户升级后也会提示一次）。弹窗不可点外部关闭，保证标记必定落库。同时修正上一条英文文案为 Unclear / saved 用语。新增测试：provider 标记与幂等、弹窗开关写回与关闭路径、精听页首次弹窗后进入讲解、弹窗内关开关后进入讲解。精听页、学习设置 provider 与弹窗相关测试通过，改动文件 `flutter analyze` 无问题。**完成时间**: 2026-10-29
 - [x] 修复精听切换收藏时抛出 `Failed to interpolate TextStyles with different inherit values`：未收藏句子点「听不太懂」旁收藏后，`PracticeNormalModeView` 的 Row 子项按位置复用 `FilledButton` element，「听不太懂」的文字样式被插值到「取消标记」按钮。修复：两个按钮加稳定 `ValueKey`。新增回归测试（修复前复现插值异常，修复后通过）；相关 practice / 精听 / 复习页测试 205 项通过，改动文件 `flutter analyze` 无问题。**完成时间**: 2026-10-29
 - [x] 学习设置新增「听不懂时自动收藏」开关（偏好 `learning_auto_favorite_on_cant_understand`，默认开启，保持原行为）：关闭后精听点击「听不太懂」只进入讲解，不再把当前句加入收藏（不改动已收藏句）；走 `LearningSettings` 与云同步白名单。新增测试：provider setter 与启动读取、精听进入讲解页开启/关闭两条路径；`learning_settings_screen_test` 的两个引导用例因新增卡片把引导区挤出默认视口，改为加高测试视口后再点击（基线 14 项通过，改后仍 14 项通过）。相关测试 provider/精听/同步/设置页合计通过，改动文件 `flutter analyze` 无问题。**完成时间**: 2026-10-29
 - [x] 学习页「为你推荐」卡片可关闭，并新增设置入口「显示设置」：推荐卡标题行右侧加关闭按钮，点击弹确认框，确认后隐藏（偏好 `learning_show_study_recommendation`，默认开启，走 `LearningSettings` 与云同步白名单）；设置页「学习」分组新增「显示设置」页，可重新开启推荐卡片。新增测试：provider setter 与启动读取、同步白名单、学习页取消/确认/设置关闭三条路径、显示设置页开关。相关测试 119 项通过，改动文件 `flutter analyze` 无问题。**完成时间**: 2026-10-29

lib/features/user_preferences/data/local_user_preferences_store.dart

@@ -35,7 +35,7 @@ class LocalUserPreferencesStore {
     LearningSettingsKeys.listenAndRepeatRatingEnabled: true,
     LearningSettingsKeys.retellRatingEnabled: true,
     LearningSettingsKeys.showStudyRecommendation: true,
-    LearningSettingsKeys.autoFavoriteOnCantUnderstand: true,
+    LearningSettingsKeys.autoSaveOnUnclear: true,
   };
 
   UserPreferencesDocument capture() {
@@ -193,8 +193,7 @@ class LocalUserPreferencesStore {
         'listenAndRepeatRatingEnabled',
     LearningSettingsKeys.retellRatingEnabled: 'retellRatingEnabled',
     LearningSettingsKeys.showStudyRecommendation: 'showStudyRecommendation',
-    LearningSettingsKeys.autoFavoriteOnCantUnderstand:
-        'autoFavoriteOnCantUnderstand',
+    LearningSettingsKeys.autoSaveOnUnclear: 'autoFavoriteOnCantUnderstand',
   };
 
   static String _learningFieldName(String storageKey) =>

lib/l10n/app_en.arb

@@ -748,7 +748,7 @@
   },
   "intensiveListenPeek": "Peek at subtitles",
   "intensiveListenHideSubtitle": "Hide subtitles",
-  "intensiveListenCantUnderstand": "Unclear",
+  "intensiveListenUnclear": "Unclear",
   "intensiveListenAutoMarkedDifficult": "Auto-save, tap to undo",
   "intensiveListenMarkedDifficult": "Unsave",
   "intensiveListenNotDifficult": "Save",
@@ -2292,8 +2292,14 @@
   "listenAndRepeatRatingSubtitle": "When off, recordings are kept but recognition and scoring are skipped",
   "retellRatingToggle": "Show rating after each retelling",
   "retellRatingSubtitle": "When off, your recording can still be played back, but scores aren't shown",
-  "autoFavoriteOnCantUnderstandToggle": "Auto-favorite when marked as hard to understand",
-  "autoFavoriteOnCantUnderstandSubtitle": "When on, tapping \"Hard to understand\" in intensive listening adds the sentence to favorites",
+  "autoSaveOnUnclearToggle": "Auto-save when marked Unclear",
+  "autoSaveOnUnclearSubtitle": "When on, tapping \"Unclear\" in intensive listening saves the sentence",
+  "unclearAutoSaveDialogTitle": "Auto-save unclear sentences",
+  "unclearAutoSaveDialogMessage": "When you tap \"Unclear\", the sentence is saved automatically so you can review it later.",
+  "unclearAutoSaveSwitchOn": "On",
+  "unclearAutoSaveSwitchOff": "Off",
+  "unclearAutoSaveDialogHint": "You can change this anytime in Me → Learning Settings.",
+  "unclearAutoSaveDialogConfirm": "Got it",
   "retellSkip": "Skip",
   "retellSkippedSuffix": "Skipped",
   "skipSilenceTitle": "Auto-skip Silence",

lib/l10n/app_localizations.dart

@@ -2450,11 +2450,11 @@ abstract class AppLocalizations {
   /// **'Hide subtitles'**
   String get intensiveListenHideSubtitle;
 
-  /// No description provided for @intensiveListenCantUnderstand.
+  /// No description provided for @intensiveListenUnclear.
   ///
   /// In en, this message translates to:
   /// **'Unclear'**
-  String get intensiveListenCantUnderstand;
+  String get intensiveListenUnclear;
 
   /// No description provided for @intensiveListenAutoMarkedDifficult.
   ///
@@ -7748,17 +7748,53 @@ abstract class AppLocalizations {
   /// **'When off, your recording can still be played back, but scores aren\'t shown'**
   String get retellRatingSubtitle;
 
-  /// No description provided for @autoFavoriteOnCantUnderstandToggle.
+  /// No description provided for @autoSaveOnUnclearToggle.
   ///
   /// In en, this message translates to:
-  /// **'Auto-favorite when marked as hard to understand'**
-  String get autoFavoriteOnCantUnderstandToggle;
+  /// **'Auto-save when marked Unclear'**
+  String get autoSaveOnUnclearToggle;
 
-  /// No description provided for @autoFavoriteOnCantUnderstandSubtitle.
+  /// No description provided for @autoSaveOnUnclearSubtitle.
   ///
   /// In en, this message translates to:
-  /// **'When on, tapping \"Hard to understand\" in intensive listening adds the sentence to favorites'**
-  String get autoFavoriteOnCantUnderstandSubtitle;
+  /// **'When on, tapping \"Unclear\" in intensive listening saves the sentence'**
+  String get autoSaveOnUnclearSubtitle;
+
+  /// No description provided for @unclearAutoSaveDialogTitle.
+  ///
+  /// In en, this message translates to:
+  /// **'Auto-save unclear sentences'**
+  String get unclearAutoSaveDialogTitle;
+
+  /// No description provided for @unclearAutoSaveDialogMessage.
+  ///
+  /// In en, this message translates to:
+  /// **'When you tap \"Unclear\", the sentence is saved automatically so you can review it later.'**
+  String get unclearAutoSaveDialogMessage;
+
+  /// No description provided for @unclearAutoSaveSwitchOn.
+  ///
+  /// In en, this message translates to:
+  /// **'On'**
+  String get unclearAutoSaveSwitchOn;
+
+  /// No description provided for @unclearAutoSaveSwitchOff.
+  ///
+  /// In en, this message translates to:
+  /// **'Off'**
+  String get unclearAutoSaveSwitchOff;
+
+  /// No description provided for @unclearAutoSaveDialogHint.
+  ///
+  /// In en, this message translates to:
+  /// **'You can change this anytime in Me → Learning Settings.'**
+  String get unclearAutoSaveDialogHint;
+
+  /// No description provided for @unclearAutoSaveDialogConfirm.
+  ///
+  /// In en, this message translates to:
+  /// **'Got it'**
+  String get unclearAutoSaveDialogConfirm;
 
   /// No description provided for @retellSkip.
   ///

lib/l10n/app_localizations_en.dart

@@ -1348,7 +1348,7 @@ class AppLocalizationsEn extends AppLocalizations {
   String get intensiveListenHideSubtitle => 'Hide subtitles';
 
   @override
-  String get intensiveListenCantUnderstand => 'Unclear';
+  String get intensiveListenUnclear => 'Unclear';
 
   @override
   String get intensiveListenAutoMarkedDifficult => 'Auto-save, tap to undo';
@@ -4433,12 +4433,31 @@ class AppLocalizationsEn extends AppLocalizations {
       'When off, your recording can still be played back, but scores aren\'t shown';
 
   @override
-  String get autoFavoriteOnCantUnderstandToggle =>
-      'Auto-favorite when marked as hard to understand';
+  String get autoSaveOnUnclearToggle => 'Auto-save when marked Unclear';
 
   @override
-  String get autoFavoriteOnCantUnderstandSubtitle =>
-      'When on, tapping \"Hard to understand\" in intensive listening adds the sentence to favorites';
+  String get autoSaveOnUnclearSubtitle =>
+      'When on, tapping \"Unclear\" in intensive listening saves the sentence';
+
+  @override
+  String get unclearAutoSaveDialogTitle => 'Auto-save unclear sentences';
+
+  @override
+  String get unclearAutoSaveDialogMessage =>
+      'When you tap \"Unclear\", the sentence is saved automatically so you can review it later.';
+
+  @override
+  String get unclearAutoSaveSwitchOn => 'On';
+
+  @override
+  String get unclearAutoSaveSwitchOff => 'Off';
+
+  @override
+  String get unclearAutoSaveDialogHint =>
+      'You can change this anytime in Me → Learning Settings.';
+
+  @override
+  String get unclearAutoSaveDialogConfirm => 'Got it';
 
   @override
   String get retellSkip => 'Skip';

lib/l10n/app_localizations_zh.dart

@@ -1308,7 +1308,7 @@ class AppLocalizationsZh extends AppLocalizations {
   String get intensiveListenHideSubtitle => '隐藏字幕';
 
   @override
-  String get intensiveListenCantUnderstand => '听不太懂';
+  String get intensiveListenUnclear => '听不太懂';
 
   @override
   String get intensiveListenAutoMarkedDifficult => '已自动收藏';
@@ -4229,10 +4229,28 @@ class AppLocalizationsZh extends AppLocalizations {
   String get retellRatingSubtitle => '关闭后只保留录音回听，不再显示评分';
 
   @override
-  String get autoFavoriteOnCantUnderstandToggle => '听不懂时自动收藏';
+  String get autoSaveOnUnclearToggle => '听不懂时自动收藏';
 
   @override
-  String get autoFavoriteOnCantUnderstandSubtitle => '精听时点击「听不太懂」，自动把该句加入收藏';
+  String get autoSaveOnUnclearSubtitle => '精听时点击「听不太懂」，自动把该句加入收藏';
+
+  @override
+  String get unclearAutoSaveDialogTitle => '自动收藏听不懂的句子';
+
+  @override
+  String get unclearAutoSaveDialogMessage => '点「听不太懂」时，会自动收藏本句，方便你之后集中复习。';
+
+  @override
+  String get unclearAutoSaveSwitchOn => '开启';
+
+  @override
+  String get unclearAutoSaveSwitchOff => '关闭';
+
+  @override
+  String get unclearAutoSaveDialogHint => '随时可在「我的 → 学习设置」中修改。';
+
+  @override
+  String get unclearAutoSaveDialogConfirm => '知道了';
 
   @override
   String get retellSkip => '跳过';

lib/l10n/app_zh.arb

@@ -545,7 +545,7 @@
   "intensiveListenPlayCount": "第 {current}/{total} 遍",
   "intensiveListenPeek": "偷看字幕",
   "intensiveListenHideSubtitle": "隐藏字幕",
-  "intensiveListenCantUnderstand": "听不太懂",
+  "intensiveListenUnclear": "听不太懂",
   "intensiveListenAutoMarkedDifficult": "已自动收藏",
   "intensiveListenMarkedDifficult": "取消收藏",
   "intensiveListenNotDifficult": "收藏",
@@ -1818,8 +1818,14 @@
   "listenAndRepeatRatingSubtitle": "关闭后保留录音回听，但不再识别和评分",
   "retellRatingToggle": "复述时显示评分",
   "retellRatingSubtitle": "关闭后只保留录音回听，不再显示评分",
-  "autoFavoriteOnCantUnderstandToggle": "听不懂时自动收藏",
-  "autoFavoriteOnCantUnderstandSubtitle": "精听时点击「听不太懂」，自动把该句加入收藏",
+  "autoSaveOnUnclearToggle": "听不懂时自动收藏",
+  "autoSaveOnUnclearSubtitle": "精听时点击「听不太懂」，自动把该句加入收藏",
+  "unclearAutoSaveDialogTitle": "自动收藏听不懂的句子",
+  "unclearAutoSaveDialogMessage": "点「听不太懂」时，会自动收藏本句，方便你之后集中复习。",
+  "unclearAutoSaveSwitchOn": "开启",
+  "unclearAutoSaveSwitchOff": "关闭",
+  "unclearAutoSaveDialogHint": "随时可在「我的 → 学习设置」中修改。",
+  "unclearAutoSaveDialogConfirm": "知道了",
   "retellSkip": "跳过",
   "retellSkippedSuffix": "已跳过",
   "skipSilenceTitle": "自动跳过静音",

lib/providers/learning_session/intensive_listen_player_provider.dart

@@ -479,21 +479,21 @@ class IntensiveListenPlayer extends _$IntensiveListenPlayer {
 
     // 「听不太懂」自动收藏受学习设置控制；关闭时只进入讲解，不改收藏状态。
     // 持久化靠对比 difficultSentences 完成，因此不加入即不写库。
-    final autoFavoriteEnabled = ref
+    final autoSaveEnabled = ref
         .read(learningSettingsProvider)
-        .autoFavoriteOnCantUnderstand;
+        .autoSaveOnUnclear;
     final newDifficult = Set<int>.from(state.difficultSentences);
     final wasAlreadyDifficult = newDifficult.contains(
       state.currentSentenceIndex,
     );
-    final shouldAutoFavorite = autoFavoriteEnabled && !wasAlreadyDifficult;
-    if (shouldAutoFavorite) {
+    final shouldAutoSave = autoSaveEnabled && !wasAlreadyDifficult;
+    if (shouldAutoSave) {
       newDifficult.add(state.currentSentenceIndex);
     }
 
     state = state.copyWith(
       difficultSentences: newDifficult,
-      isCurrentSentenceAutoMarked: shouldAutoFavorite,
+      isCurrentSentenceAutoMarked: shouldAutoSave,
       isTextRevealed: false,
       playingSenseGroupIndex: null,
       playedSenseGroupIndices: const {},