v0.3.4: Bug修复+性能优化+文档大纲功能

🔴 Bug修复 (6):
- Sidebar反斜杠正则修复 (Windows路径规范化)
- FileWatcher文件删除后自动恢复监听
- SearchReplace replaceAll防过期匹配位置
- openFolderDialog null结果守卫
- 保存异常时空路径保护
- Markdown绝对路径图片拼接修复

🟡 性能优化:
- Editor切换标签时内容比较，相同跳过replaceAll

🔵 代码质量:
- 创建共享常量模块 src/shared/constants.ts，消除双副本

🎯 新增功能:
- 文档大纲 (Table of Contents) — 侧边栏标题导航

🔧 换行符统一: CRLF → LF

src/renderer/components/SearchReplace/SearchReplace.tsx

@@ -205,17 +205,21 @@ export const SearchReplace = memo(function SearchReplace({
     const view = getView()
     if (!view) return
 
-    const matches = matchesRef.current
-    if (matches.length === 0) return
+    // 重新搜索以获取匹配的最新位置
+    const freshMatches = findMatches(view.state.doc, queryRef.current, caseSensitiveRef.current)
+    if (freshMatches.length === 0) return
 
-    // Process matches in reverse order to preserve positions
+    // 从后往前替换以保持位置正确
     const tr = view.state.tr
-    for (let i = matches.length - 1; i >= 0; i--) {
-      tr.insertText(replacement, matches[i].from, matches[i].to)
+    for (let i = freshMatches.length - 1; i >= 0; i--) {
+      tr.insertText(replacement, freshMatches[i].from, freshMatches[i].to)
     }
     view.dispatch(tr)
 
-    // Re-search after replacement
+    // 更新ref
+    matchesRef.current = []
+
+    // 替换后重新搜索
     requestAnimationFrame(() => {
       doSearch(queryRef.current, caseSensitiveRef.current)
     })