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/models/models.py

@@ -14,6 +14,7 @@ class Project(Base, UUIDMixin, TimestampMixin):
 
     name = Column(String(255), nullable=False)
     description = Column(Text)
+    type = Column(String(50), default="qa")  # qa, table, database
 
     # Relationships
     files = relationship("File", back_populates="project", cascade="all, delete-orphan")