发货链接返回完整域名：DELIVERY_BASE_URL 未配置时按请求 scheme+Host 推导

- GetOrCreateDeliveryLink/RestoreDeliveryLink 增加 requestBaseURL 参数
- buildDeliveryURL 优先级：DELIVERY_BASE_URL → 请求域名 → 路径
- 支持 X-Forwarded-Proto 与 TLS 判断 https

backend/internal/handler/base_url.go

@@ -0,0 +1,18 @@
+package handler
+
+import (
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+// requestBaseURL 根据当前请求推导站点基础地址（如 https://skin.khhao.com）。
+// 优先取配置的 DELIVERY_BASE_URL（服务层），为空时由请求的 scheme + Host 推导，
+// 保证发货链接始终返回完整可访问的 URL。
+func requestBaseURL(c *gin.Context) string {
+	scheme := "http"
+	if c.Request.TLS != nil || strings.EqualFold(c.GetHeader("X-Forwarded-Proto"), "https") {
+		scheme = "https"
+	}
+	return scheme + "://" + c.Request.Host
+}

backend/internal/handler/merchant.go

@@ -168,7 +168,7 @@ func (h *MerchantHandler) CreateTestOrder(c *gin.Context) {
 }
 
 func (h *MerchantHandler) GetDeliveryLink(c *gin.Context) {
-	link, err := h.deliverySvc.GetOrCreateDeliveryLink(middleware.GetMerchantID(c), c.Param("order_no"))
+	link, err := h.deliverySvc.GetOrCreateDeliveryLink(middleware.GetMerchantID(c), c.Param("order_no"), requestBaseURL(c))
 	if err != nil {
 		writeDeliveryError(c, err)
 		return
@@ -185,7 +185,7 @@ func (h *MerchantHandler) RevokeDeliveryLink(c *gin.Context) {
 }
 
 func (h *MerchantHandler) RestoreDeliveryLink(c *gin.Context) {
-	link, err := h.deliverySvc.RestoreDeliveryLink(middleware.GetMerchantID(c), c.Param("order_no"))
+	link, err := h.deliverySvc.RestoreDeliveryLink(middleware.GetMerchantID(c), c.Param("order_no"), requestBaseURL(c))
 	if err != nil {
 		writeDeliveryError(c, err)
 		return

backend/internal/handler/open_v1.go

@@ -163,7 +163,7 @@ func (h *OpenV1Handler) GetDeliveryLink(c *gin.Context) {
 	openlog.SetAction(c, openlog.ActionQuery)
 	orderNo := c.Param("order_no")
 	openlog.Info(c, "delivery_link start order_no=%s", orderNo)
-	link, err := h.deliverySvc.GetOrCreateDeliveryLink(middleware.GetMerchantID(c), orderNo)
+	link, err := h.deliverySvc.GetOrCreateDeliveryLink(middleware.GetMerchantID(c), orderNo, requestBaseURL(c))
 	if err != nil {
 		openlog.Warn(c, "delivery_link fail order_no=%s err=%v", orderNo, err)
 		if sc, ok := err.(interface{ HTTPStatus() int }); ok {