优化订单履约状态处理

backend/internal/service/delivery.go

@@ -345,7 +345,7 @@ func (s *DeliveryService) claimDeliverySubmission(merchantID, apiClientID uint,
 			updated = order
 			return nil
 		}
-		if order.FulfillmentStatus != model.FulfillmentStatusPending && order.FulfillmentStatus != model.FulfillmentStatusFailed {
+		if err := validateFulfillmentTransition(&order, model.FulfillmentStatusProcessing, fulfillmentTransitionUpdate); err != nil {
 			return newDeliveryHTTPError(http.StatusConflict, "订单暂不可发货")
 		}
 		raw, _ := json.Marshal(map[string]interface{}{