v0.2.0: 全面代码质量优化

- ESLint flat config + Prettier + EditorConfig
- Markdown处理器LRU缓存
- Zustand选择器优化减少重渲染
- CodeMirror Compartment主题热切换
- Preview防抖(150ms) + IndexedDB去抖(500ms)
- 组件拆分: App.tsx 310→104行, Sidebar.tsx 244→90行
- 统一错误处理 errorHandler.ts
- ConfirmDialog替代原生confirm
- LoadingSpinner加载状态
- Toast多条堆叠+类型区分
- 可访问性增强(ARIA属性、键盘导航)
- Vitest测试框架(78个测试用例)
- Git hooks(husky + lint-staged)
- 项目文档(README.md, CONTRIBUTING.md)

src/renderer/hooks/useTheme.ts

@@ -1,29 +1,21 @@
-import { useEffect, useRef } from 'react'
+import { useEffect } from 'react'
 import { useEditorStore } from '../stores/editorStore'
 import { settingsRepository } from '../db/settingsRepository'
 
+/**
+ * AR-04: 主题 hook
+ * 不再独立加载设置（由 useSettingsInit 统一加载）
+ * 仅负责主题切换时的同步和保存
+ */
 export function useTheme() {
   const darkMode = useEditorStore(s => s.darkMode)
-  const setDarkMode = useEditorStore(s => s.setDarkMode)
-  const isInitialized = useRef(false)
+  const toggleDarkMode = useEditorStore(s => s.toggleDarkMode)
 
-  // B-05: 从 IndexedDB 加载主题设置
+  // darkMode 变化时同步 class 并保存
   useEffect(() => {
-    settingsRepository.load().then(settings => {
-      const prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches
-      setDarkMode(settings.darkMode !== undefined ? settings.darkMode : prefersDark)
-      isInitialized.current = true
-    }).catch(err => console.error('Failed to load theme settings:', err))
-  }, [setDarkMode])
-
-  // B-05: 首次加载完成后才保存主题设置
-  useEffect(() => {
-    if (!isInitialized.current) return
     document.documentElement.classList.toggle('dark', darkMode)
     settingsRepository.save({ darkMode })
   }, [darkMode])
 
-  const toggleDarkMode = useEditorStore(s => s.toggleDarkMode)
-
   return { darkMode, toggleDarkMode }
 }