v0.3.10: 全面优化增强 — 17项Bug修复/稳定性/功能改进

P0 致命Bug修复:
- A1: openFolderDialog 类型/运行时崩溃(文件夹打开功能完全失效)
- A2: SourceEditor 受控textarea手动改DOM反模式
- A3: tabStore.updateTabContent 内容相同时误标isModified

死代码清理:
- B1: 删除menu:*/save/as/viewMode 三个永不触发的IPC通道

健壮性修复:
- E1: rehypeFixImages 路径规范化+防越界加固
- E2: getFileName 尾斜杠返回正确文件名
- E3: EditorToolbar 行内代码按钮改用toggleInlineCodeCommand
- E4: ErrorBoundary 内联样式抽为CSS类

功能增强:
- D1: 标签页拖拽排序(tabStore.moveTab + TabBar DnD + CSS)
- D2: Milkdown自动配对括号/引号(ProseMirror插件)
- D3: 状态栏自动保存开关可点击
- D4: 文档大纲活跃标题高亮(useActiveHeading hook)
- D5: 关闭窗口前flush防抖数据(flushSaveToDB)
- D6: 搜索替换支持正则表达式

类型/架构:
- C2: preload类型集中定义(ElectronAPI契约)
- __pycache__ typo修复

文档/版本:
- README/DESIGN同步为Milkdown + v0.3.10
- 项目结构树/技术栈/快捷键表更新

验证: typecheck(仅7预存), lint✅, test 96/96, vite build✅

src/renderer/hooks/useFolderOperations.ts

@@ -15,22 +15,19 @@ export function useFolderOperations() {
 
   const handleOpenFolder = useCallback(async () => {
     if (!window.electronAPI) return
-    const result = await window.electronAPI.openFolderDialog()
-    if (!result) return
-    if (!result.canceled && result.filePaths[0]) {
-      const dirPath = result.filePaths[0]
-      setRootPath(dirPath)
-      expandDirs([dirPath])
-      setLoading('dir-load', true)
-      try {
-        const dirTree = await window.electronAPI.readDirTree(dirPath)
-        if (dirTree.success && dirTree.tree) {
-          setTree(dirTree.tree)
-          window.electronAPI.watchDir(dirPath)
-        }
-      } finally {
-        setLoading('dir-load', false)
+    const dirPath = await window.electronAPI.openFolderDialog()
+    if (!dirPath) return
+    setRootPath(dirPath)
+    expandDirs([dirPath])
+    setLoading('dir-load', true)
+    try {
+      const dirTree = await window.electronAPI.readDirTree(dirPath)
+      if (dirTree.success && dirTree.tree) {
+        setTree(dirTree.tree)
+        window.electronAPI.watchDir(dirPath)
       }
+    } finally {
+      setLoading('dir-load', false)
     }
   }, [setRootPath, setTree, expandDirs, setLoading])