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>

frontend/package.json

@@ -10,6 +10,7 @@
   "dependencies": {
     "@element-plus/icons-vue": "^2.3.0",
     "@vueuse/core": "^11.0.0",
+    "ant-design-vue": "^4.2.6",
     "axios": "^1.7.0",
     "element-plus": "^2.8.0",
     "pinia": "^2.2.0",