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

eslint.config.mjs

@@ -1,28 +1,28 @@
-import eslint from '@eslint/js'
-import tseslint from 'typescript-eslint'
-import reactHooks from 'eslint-plugin-react-hooks'
-import reactRefresh from 'eslint-plugin-react-refresh'
-
-export default tseslint.config(
-  eslint.configs.recommended,
-  ...tseslint.configs.recommended,
-  {
-    plugins: {
-      'react-hooks': reactHooks,
-      'react-refresh': reactRefresh,
-    },
-    rules: {
-      ...reactHooks.configs.recommended.rules,
-      'react-refresh/only-export-components': [
-        'warn',
-        { allowConstantExport: true },
-      ],
-      '@typescript-eslint/no-unused-vars': 'error',
-      'no-console': 'warn',
-      'prefer-const': 'error',
-    },
-  },
-  {
-    ignores: ['dist/', 'node_modules/', 'assets/', 'lib/'],
-  },
-)
+import eslint from '@eslint/js'
+import tseslint from 'typescript-eslint'
+import reactHooks from 'eslint-plugin-react-hooks'
+import reactRefresh from 'eslint-plugin-react-refresh'
+
+export default tseslint.config(
+  eslint.configs.recommended,
+  ...tseslint.configs.recommended,
+  {
+    plugins: {
+      'react-hooks': reactHooks,
+      'react-refresh': reactRefresh,
+    },
+    rules: {
+      ...reactHooks.configs.recommended.rules,
+      'react-refresh/only-export-components': [
+        'warn',
+        { allowConstantExport: true },
+      ],
+      '@typescript-eslint/no-unused-vars': 'error',
+      'no-console': 'warn',
+      'prefer-const': 'error',
+    },
+  },
+  {
+    ignores: ['dist/', 'node_modules/', 'assets/', 'lib/'],
+  },
+)