feat: 添加文稿管理、素材库、设置页面及对照检查重写功能

- 新增 DocumentsPanel.vue 文稿管理页面
- 新增 MaterialsPanel.vue 素材库管理页面
- 新增 SettingsPanel.vue 设置页面
- 新增 DocumentSelectorModal.vue 文稿选择弹窗
- 新增 MaterialSelectorModal.vue 素材选择弹窗
- 集成 SQLite 数据库持久化 (sql.js)
- 对照检查页面支持从文稿库选取内容
- 对照检查页面新增一键重写及差异对比功能
- 修复对照检查页面布局问题
- MainContent 支持文稿编辑功能

src/App.vue

@@ -8,6 +8,9 @@
       <!-- 左侧面板 -->
       <WriterPanel v-if="currentPage === 'writer'" />
       <AnalysisPanel v-else-if="currentPage === 'analysis'" />
+      <DocumentsPanel v-else-if="currentPage === 'documents'" />
+      <MaterialsPanel v-else-if="currentPage === 'materials'" />
+      <SettingsPanel v-else-if="currentPage === 'settings'" />
       
       <!-- 右侧主内容区 -->
       <MainContent />
@@ -20,6 +23,9 @@ import { computed } from 'vue'
 import { useAppStore } from './stores/app'
 import WriterPanel from './components/WriterPanel.vue'
 import AnalysisPanel from './components/AnalysisPanel.vue'
+import DocumentsPanel from './components/DocumentsPanel.vue'
+import MaterialsPanel from './components/MaterialsPanel.vue'
+import SettingsPanel from './components/SettingsPanel.vue'
 import MainContent from './components/MainContent.vue'
 import ComparePanel from './components/ComparePanel.vue'