已完成用户APP首期功能开发

交付用户端首期页面、配套接口、后台资源及测试文档。用户APP构建、静态分析和三个管理后台构建通过；完整测试仍有2项失败，后端模型注释检查未通过，详见交付记录。

backend/api/internal/routers/upload.go

@@ -12,4 +12,6 @@ func registerUploadRoute(serviceKey string, engine *gin.Engine) {
 	authorized.Use(sdkmiddleware.JwtAuth(true))
 	authorized.POST("/file", upload.UploadFile)
 	authorized.POST("/avatar", upload.UploadAvatar)
+	authorized.POST("/product-image", upload.UploadProductImage)
+	engine.GET("/uploads/product-images/:name", upload.ServeProductImage)
 }