refactor(frontend): 更新项目视图和文本分割页面

- App.vue: 更新样式和路由配置
- ProjectView.vue: 布局调整
- TextSplit.vue: 分割功能完善

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/views/ProjectView.vue

@@ -64,7 +64,7 @@ const project = ref({ name: '加载中...', description: '' })
 
 const navItems = [
   { path: 'files', label: '文件管理', icon: 'Folder' },
-  { path: 'split', label: '文本分割', icon: 'Operation' },
+  { path: 'split', label: '分割生成', icon: 'Operation' },
   { path: 'questions', label: '问答管理', icon: 'ChatDotSquare' },
   { path: 'datasets', label: '数据集', icon: 'Collection' },
   { path: 'eval', label: '评估系统', icon: 'DataAnalysis' },