FEAT: 收藏页支持导出收藏句子与词汇为 PDF

- 收藏页右上角新增「导出 PDF」，弹窗可选导出句子、词汇或两者
- 句子按来源材料分组并附本地译文；词汇按字母序，附释义、例句与来源句
- 来源材料前显示音频/视频图标，来源行左对齐并缩进
- 导出数据全部只读本地缓存，不发起任何 API 请求
- 学习材料与收藏导出共用 PDF 底层（字体资源、版式外壳、保存/分享、预览组件）
- 学习材料导出的菜单图标改为导出图标；PDF 首页去掉标题分隔线，品牌字间距收窄

Author: echo-loop

PLAN.md

@@ -1,6 +1,6 @@
 # Echo Loop 项目规划
 
-> 最后更新：2026-11-13（账户页新增用量与额度进度条）
+> 最后更新：2026-11-14（收藏导出 PDF）
 > 当前焦点：录音 + 识别功能；首要阻塞为 Android 离线 ASR 结束录音闪退
 
 ## 产品目标
@@ -20,7 +20,7 @@ Echo Loop 是一个围绕“音频输入 + 句子级学习 + 间隔复习 + AI 
 - 收藏体系：句子、单词、意群、收藏复习。
 - 词典体系：在线词典（后端 API + 本地缓存表）、AI 词典、网页词典、多源切换、非 modal 面板、手动查词页（本地词表前缀建议 + 本地查询历史，学习页入口）。
 - AI 能力：翻译、句子解析、单词深度解析、转录。
-- PDF 导出：学习材料导出为可打印 PDF。
+- PDF 导出：学习材料与收藏（句子 / 词汇）导出为可打印 PDF，共用渲染底层。
 - 订阅体系：平台/渠道识别、native RevenueCat、direct Paddle 后端结账、AI 配额后端裁决。
 
 当前主要风险：

TASKS.md

@@ -29,6 +29,9 @@
   - [x] 云端偏好同步接入字幕文字字号与粗细：本地键 `subtitle_font_size_percent` / `subtitle_font_weight_percent`，云端字段 `appearance.subtitleFontSizePercent` / `appearance.subtitleFontWeightPercent`（后端按域名校验、域内字段自由，无需改后端）；云端缺失或非法时保留本地值。**完成时间**: 2026-11-12
 - [x] 收藏词汇复习设置新增「正面显示释义」（默认关闭，仅对单词有效，先取基础在线词典（本地缓存 → API），未查到时只读 AI 查词缓存，经偏好同步跨平台）。**完成时间**: 2026-11-13
   - 未完成的验证：真机确认正面释义的加载/占位观感，以及两台设备切换后同步生效。
+- [x] 收藏导出 PDF：收藏页右上角「导出」弹窗选择句子 / 词汇（可同时导出），句子按来源材料分组并附本地译文，词汇按字母序并附本地释义（AI 查词首义项与首例句，单词回落基础词典首行释义）与来源句。全部只读本地缓存，不发起任何 API 请求。PDF 底层（字体、版式外壳、保存 / 分享、预览）与学习材料导出共用（`services/pdf_export/common/`、`widgets/pdf/`）；导出数据与格式解耦，新增格式只需加 `FavoritesExportFormat` 枚举值并补渲染分支。**完成时间**: 2026-11-14
+  - 未完成的验证：真机确认收藏 PDF 的中文字体、分页与长词条观感，以及下载 / 分享流程（iOS / Android / macOS）。
+- [ ] 学习材料 PDF 读取 AI 词典缓存时仍使用旧类型 `ai_dictionary`，而当前写入类型为 `ai_dictionary_v2`，导致学习材料 PDF 读不到 AI 查词结果；收藏导出已改用 `AiDictionarySource.readCachedEntry`。需确认后统一修正。
 - [ ] 查词归一化 Unicode 化，并迁移已有收藏 key（需产品与数据决策）。
 - [ ] 计算并展示每个学习任务的预计/实际耗时。
 - [ ] 学习 Tab 点击学习/复习后直接进入学习页面，跳过学习计划页。

lib/database/daos/audio_item_dao.dart

@@ -7,6 +7,9 @@ part 'audio_item_dao.g.dart';
 
 /// 音频元数据 DAO
 /// 提供音频项的 CRUD 操作
+/// 未删除音频的来源信息（名称 + 路径，媒体类型由路径扩展名判定）
+typedef ActiveAudioSource = ({String name, String? audioPath});
+
 @DriftAccessor(tables: [AudioItems])
 class AudioItemDao extends DatabaseAccessor<AppDatabase>
     with _$AudioItemDaoMixin {
@@ -41,6 +44,24 @@ class AudioItemDao extends DatabaseAccessor<AppDatabase>
     )..where((t) => t.id.equals(id))).getSingleOrNull();
   }
 
+  /// 批量获取未软删除音频的来源信息（audioItemId → 名称与路径）
+  ///
+  /// 已删除或不存在的 ID 不在结果中，调用方据此显示「未知来源」。
+  /// 媒体类型由调用方按 audioPath 判定，DAO 只返回数据。
+  Future<Map<String, ActiveAudioSource>> getActiveSourcesByIds(
+    Iterable<String> ids,
+  ) async {
+    final idList = ids.toList();
+    if (idList.isEmpty) return {};
+    final rows = await (select(
+      audioItems,
+    )..where((t) => t.id.isIn(idList) & t.deletedAt.isNull())).get();
+    return {
+      for (final row in rows)
+        row.id: (name: row.name, audioPath: row.audioPath),
+    };
+  }
+
   /// 根据社区合集中的 remoteAudioId 反查本地行。
   ///
   /// 同步时用于判断"远端新增音频在本地是否已存在"；忽略软删除行，避免复用

lib/database/daos/bookmark_dao.dart

@@ -178,28 +178,33 @@ class BookmarkDao extends DatabaseAccessor<AppDatabase>
   ///
   /// JOIN audio_items 获取音频名称，用于 Favorites 页面展示。
   /// 音频已删除（CASCADE）的书签不会出现在结果中。
-  Stream<List<BookmarkWithAudio>> watchAllWithAudioName() {
-    final query =
-        select(bookmarks).join([
-            innerJoin(
-              audioItems,
-              audioItems.id.equalsExp(bookmarks.audioItemId),
-            ),
-          ])
-          ..where(bookmarks.deletedAt.isNull() & audioItems.deletedAt.isNull())
-          ..orderBy([
-            OrderingTerm.asc(audioItems.name),
-            OrderingTerm.asc(bookmarks.sentenceIndex),
-          ]);
+  Stream<List<BookmarkWithAudio>> watchAllWithAudioName() =>
+      _activeWithAudioQuery().watch().map(_toBookmarksWithAudio);
 
-    return query.watch().map((rows) {
-      return rows.map((row) {
-        return BookmarkWithAudio(
-          bookmark: row.readTable(bookmarks),
-          audioName: row.readTable(audioItems).name,
-        );
-      }).toList();
-    });
+  /// 一次性读取所有未删除书签（含音频名称），口径同 [watchAllWithAudioName]
+  ///
+  /// 供导出等非流式场景使用。
+  Future<List<BookmarkWithAudio>> getAllWithAudioName() async =>
+      _toBookmarksWithAudio(await _activeWithAudioQuery().get());
+
+  JoinedSelectStatement<HasResultSet, dynamic> _activeWithAudioQuery() {
+    return select(bookmarks).join([
+        innerJoin(audioItems, audioItems.id.equalsExp(bookmarks.audioItemId)),
+      ])
+      ..where(bookmarks.deletedAt.isNull() & audioItems.deletedAt.isNull())
+      ..orderBy([
+        OrderingTerm.asc(audioItems.name),
+        OrderingTerm.asc(bookmarks.sentenceIndex),
+      ]);
+  }
+
+  List<BookmarkWithAudio> _toBookmarksWithAudio(List<TypedResult> rows) {
+    return rows.map((row) {
+      return BookmarkWithAudio(
+        bookmark: row.readTable(bookmarks),
+        audioName: row.readTable(audioItems).name,
+      );
+    }).toList();
   }
 
   /// 获取所有已软删除的书签（含音频名称）

lib/l10n/app_en.arb

@@ -2424,5 +2424,47 @@
   "shareCardSaved": "Image saved",
   "shareCardActionFailed": "Could not complete the action. Please try again.",
   "shareCardPermissionDenied": "Allow photo access in system settings to save your card.",
-  "shareCardNotSignedIn": "Sign in to share your card."
+  "shareCardNotSignedIn": "Sign in to share your card.",
+  "favoritesExportMenu": "Export PDF",
+  "@favoritesExportMenu": {
+    "description": "Favorites tab overflow menu item that opens the export dialog"
+  },
+  "favoritesExportDialogTitle": "Export saved items",
+  "@favoritesExportDialogTitle": {
+    "description": "Title of the favorites export options dialog"
+  },
+  "favoritesExportSentencesOption": "Saved sentences ({count})",
+  "@favoritesExportSentencesOption": {
+    "description": "Checkbox to include saved sentences in the favorites export",
+    "placeholders": {
+      "count": {"type": "int"}
+    }
+  },
+  "favoritesExportWordsOption": "Saved vocabulary ({count})",
+  "@favoritesExportWordsOption": {
+    "description": "Checkbox to include saved words and phrases in the favorites export",
+    "placeholders": {
+      "count": {"type": "int"}
+    }
+  },
+  "favoritesExportConfirm": "Export",
+  "@favoritesExportConfirm": {
+    "description": "Confirm button of the favorites export options dialog"
+  },
+  "favoritesExportTitle": "Saved Items",
+  "@favoritesExportTitle": {
+    "description": "Document title of the exported favorites PDF"
+  },
+  "favoritesExportSentencesSection": "Sentences",
+  "@favoritesExportSentencesSection": {
+    "description": "Section heading of saved sentences in the favorites PDF"
+  },
+  "favoritesExportWordsSection": "Vocabulary",
+  "@favoritesExportWordsSection": {
+    "description": "Section heading of saved words in the favorites PDF"
+  },
+  "favoritesExportUnknownSource": "Unknown source",
+  "@favoritesExportUnknownSource": {
+    "description": "Placeholder for a favorite whose source material was deleted"
+  }
 }

lib/l10n/app_localizations.dart

@@ -9295,6 +9295,60 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Sign in to share your card.'**
   String get shareCardNotSignedIn;
+
+  /// Favorites tab overflow menu item that opens the export dialog
+  ///
+  /// In en, this message translates to:
+  /// **'Export PDF'**
+  String get favoritesExportMenu;
+
+  /// Title of the favorites export options dialog
+  ///
+  /// In en, this message translates to:
+  /// **'Export saved items'**
+  String get favoritesExportDialogTitle;
+
+  /// Checkbox to include saved sentences in the favorites export
+  ///
+  /// In en, this message translates to:
+  /// **'Saved sentences ({count})'**
+  String favoritesExportSentencesOption(int count);
+
+  /// Checkbox to include saved words and phrases in the favorites export
+  ///
+  /// In en, this message translates to:
+  /// **'Saved vocabulary ({count})'**
+  String favoritesExportWordsOption(int count);
+
+  /// Confirm button of the favorites export options dialog
+  ///
+  /// In en, this message translates to:
+  /// **'Export'**
+  String get favoritesExportConfirm;
+
+  /// Document title of the exported favorites PDF
+  ///
+  /// In en, this message translates to:
+  /// **'Saved Items'**
+  String get favoritesExportTitle;
+
+  /// Section heading of saved sentences in the favorites PDF
+  ///
+  /// In en, this message translates to:
+  /// **'Sentences'**
+  String get favoritesExportSentencesSection;
+
+  /// Section heading of saved words in the favorites PDF
+  ///
+  /// In en, this message translates to:
+  /// **'Vocabulary'**
+  String get favoritesExportWordsSection;
+
+  /// Placeholder for a favorite whose source material was deleted
+  ///
+  /// In en, this message translates to:
+  /// **'Unknown source'**
+  String get favoritesExportUnknownSource;
 }
 
 class _AppLocalizationsDelegate

lib/l10n/app_localizations_en.dart

@@ -5249,4 +5249,35 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get shareCardNotSignedIn => 'Sign in to share your card.';
+
+  @override
+  String get favoritesExportMenu => 'Export PDF';
+
+  @override
+  String get favoritesExportDialogTitle => 'Export saved items';
+
+  @override
+  String favoritesExportSentencesOption(int count) {
+    return 'Saved sentences ($count)';
+  }
+
+  @override
+  String favoritesExportWordsOption(int count) {
+    return 'Saved vocabulary ($count)';
+  }
+
+  @override
+  String get favoritesExportConfirm => 'Export';
+
+  @override
+  String get favoritesExportTitle => 'Saved Items';
+
+  @override
+  String get favoritesExportSentencesSection => 'Sentences';
+
+  @override
+  String get favoritesExportWordsSection => 'Vocabulary';
+
+  @override
+  String get favoritesExportUnknownSource => 'Unknown source';
 }

lib/l10n/app_localizations_zh.dart

@@ -4990,4 +4990,35 @@ class AppLocalizationsZh extends AppLocalizations {
 
   @override
   String get shareCardNotSignedIn => '请先登录后分享';
+
+  @override
+  String get favoritesExportMenu => '导出 PDF';
+
+  @override
+  String get favoritesExportDialogTitle => '导出收藏';
+
+  @override
+  String favoritesExportSentencesOption(int count) {
+    return '收藏句子（$count）';
+  }
+
+  @override
+  String favoritesExportWordsOption(int count) {
+    return '收藏词汇（$count）';
+  }
+
+  @override
+  String get favoritesExportConfirm => '导出';
+
+  @override
+  String get favoritesExportTitle => '收藏清单';
+
+  @override
+  String get favoritesExportSentencesSection => '句子';
+
+  @override
+  String get favoritesExportWordsSection => '词汇';
+
+  @override
+  String get favoritesExportUnknownSource => '未知来源';
 }

lib/l10n/app_zh.arb

@@ -2048,5 +2048,14 @@
   "shareCardSaved": "图片已保存",
   "shareCardActionFailed": "操作失败，请稍后重试",
   "shareCardPermissionDenied": "没有保存图片的权限，请在系统设置中允许访问相册",
-  "shareCardNotSignedIn": "请先登录后分享"
+  "shareCardNotSignedIn": "请先登录后分享",
+  "favoritesExportMenu": "导出 PDF",
+  "favoritesExportDialogTitle": "导出收藏",
+  "favoritesExportSentencesOption": "收藏句子（{count}）",
+  "favoritesExportWordsOption": "收藏词汇（{count}）",
+  "favoritesExportConfirm": "导出",
+  "favoritesExportTitle": "收藏清单",
+  "favoritesExportSentencesSection": "句子",
+  "favoritesExportWordsSection": "词汇",
+  "favoritesExportUnknownSource": "未知来源"
 }