feat(frontend): 认证体系 + 类型定义 + API 服务层

认证:
- AuthContext + useAuth (JWT token 持久化, 登录/登出)
- AdminLoginPage (登录表单, 对接 POST /auth/login)
- axios 拦截器自动注入 Authorization header
- 401 自动清除 token 并跳转登录页

类型:
- api.ts: TASK_STATUS 常量, TaskResponse/ProductScanResponse 扩展字段
- admin.ts: ProductResponse 扩展 + MaterialOption/BomItem

API 服务:
- authApi: login() + getMe()
- materialApi: fetchMaterialGroups() + fetchMaterialItems()
- printApi: getLabelPreview() + executePrint() + getPrinterConfig()
- antd 6.5.3 依赖

字体: simhei.ttf (标签打印用)

frontend/src/types/admin.ts

@@ -3,11 +3,26 @@
 export interface ProductResponse {
   id: string;
   serial_number: string;
-  order_id: string;
-  order_no?: string;
+  external_serial: string | null;
+  order_id: string | null;
+  order_no: string;
   material_id: string | null;
+  material_name: string | null;
+  spec_model: string | null;
+  category: string | null;
+  material_type: string | null;
   parent_product_id: string | null;
   current_location_id: string | null;
   status: string;
   created_at: string;
 }
+
+/** MOM 物料选项 */
+export interface MaterialOption {
+  id: number;
+  name: string;
+  spec: string;
+  category: string;
+  type: string;
+  unit: string;
+}