feat: remove shipping settings, use shipping templates for cart calculation

backend/internal/api/handlers/shipping_template.go

@@ -258,3 +258,20 @@ func CalculateShippingFee(templateID *uint, weight float64, quantity int, subtot
 
 	return template.FirstFee + additionalCount*template.AdditionalFee, nil
 }
+
+// CalculateForUser 用户端计算运费接口
+func (h *ShippingTemplateHandler) CalculateForUser(c *gin.Context) {
+	var req schemas.CalculateShippingRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	fee, err := CalculateShippingFee(req.TemplateID, req.Weight, req.Quantity, req.Subtotal, req.Province)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "计算运费失败"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"data": gin.H{"shipping_fee": fee}})
+}

backend/internal/api/routes/routes.go

@@ -72,6 +72,7 @@ func SetupRoutes(r *gin.Engine) {
 		api.GET("/settings/public", systemHandler.GetPublicSettings)
 		api.GET("/payment-channels", paymentChannelHandler.PublicList)
 		api.POST("/payment/bepusdt/notify", paymentHandler.BepUsdtNotify)
+		api.POST("/shipping/calculate", shippingTemplateHandler.CalculateForUser)
 
 		authed := api.Group("")
 		authed.Use(middlewares.AuthMiddleware())

backend/internal/schemas/shipping_template.go

@@ -26,4 +26,13 @@ type UpdateShippingTemplateRequest struct {
 	Provinces      []string `json:"provinces"`
 	IsDefault      *bool    `json:"is_default"`
 	SortOrder      *int     `json:"sort_order"`
+}
+
+// CalculateShippingRequest 计算运费请求
+type CalculateShippingRequest struct {
+	TemplateID *uint   `json:"template_id"`
+	Weight     float64 `json:"weight"`
+	Quantity   int     `json:"quantity"`
+	Subtotal   float64 `json:"subtotal"`
+	Province   string  `json:"province"`
 }