feat: OneNote-style notebooks, text fonts, and page navigation

Add notebook.json containers with multi-member pages, fix PDF text
editing (size/bold/drag/double-tap), index SidecarText in search, and
share keyboard page shortcuts plus a PDF scrubber.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/l10n/app_localizations_zh.dart

@@ -580,4 +580,36 @@ class AppLocalizationsZh extends AppLocalizations {
 
   @override
   String get processingOcr => '正在识别文字…';
+
+  @override
+  String get notebooksSection => '笔记本';
+
+  @override
+  String get addBlankPage => '空白页';
+
+  @override
+  String get importIntoNotebook => '导入到笔记本';
+
+  @override
+  String get notebookMembersEmpty => '还没有页面';
+
+  @override
+  String memberCount(int count) {
+    return '$count 项';
+  }
+
+  @override
+  String get textFontSmall => '小';
+
+  @override
+  String get textFontMedium => '中';
+
+  @override
+  String get textFontLarge => '大';
+
+  @override
+  String get textBold => '粗体';
+
+  @override
+  String get textDragHint => '拖动移动';
 }