v1.2.1

新增：内置插件「PDF及图片高精度解析（pdf2doc）」支持将 PDF/图片解析为 Markdown/Docx 并翻译（含手写/布局/公式/表格）
优化：阅读模式 KaTeX 渲染改为时间切片/空闲渲染，避免大量公式文档导致 UI 假死
优化：所见模式 KaTeX 渲染改为可视区域附近再渲染，并对小公式缓存，提升大文档性能
修复：阅读模式中将大纲剥离到右侧后，预览滚动条被遮挡导致不可见的问题

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Added: Built-in “High-Accuracy PDF & Image Parsing (pdf2doc)” plugin — parse PDF/images into Markdown/Docx with translation (handwriting/layout/formulas/tables supported)
Improved: Reading mode KaTeX rendering now uses time-slicing/idle rendering to avoid UI freezes on formula-heavy documents
Improved: WYSIWYG KaTeX rendering now renders near-viewport math only, with small-formula caching for better performance on large documents
Fixed: In reading mode, when the Outline is detached to the right, the preview scrollbar could be covered and become invisible