feat: 完善前端功能，添加爬虫页面和项目分页

- 新增 CrawlerView 爬虫页面
- 完善 HomeView 分页展示（9个/页）
- 更新 ProjectCard 组件图标
- 优化 API 客户端和类型定义
- 重构样式文件结构到独立目录

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

backend/app/api/v1/projects/__init__.py

@@ -27,7 +27,7 @@ logger = logging.getLogger("yg_dataset.projects")
 project_crud = CRUDBase(Project)
 
 
-@router.get("", response_model=ApiResponse)
+@router.get("", response_model=PaginatedResponse)
 async def list_projects(
     page: int = Query(1, ge=1, description="Page number"),
     page_size: int = Query(20, ge=1, le=100, description="Page size"),