对接文档去除上游概念，只展示商户对接平台

- 文档移除所有上游/发货平台/BFF 表述：接口字段说明、示例、推荐流程全部中性化
- 代码用户可见文案同步中性化：提交发货 message、错误提示、发货配置相关措辞
- 概述去掉 /api/open/v1 上游链路提示

backend/internal/service/delivery.go

@@ -231,7 +231,7 @@ func (s *DeliveryService) bindGood(gameAccount, goodID string) (*DeliveryBindRes
 		return nil, err
 	}
 	if out.BindUUID == "" || out.URL == "" {
-		return nil, errors.New("上游未返回绑定二维码")
+		return nil, errors.New("绑定服务未返回绑定二维码")
 	}
 	return &DeliveryBindResult{
 		BindUUID: out.BindUUID,
@@ -284,7 +284,7 @@ func (s *DeliveryService) submit(orderNo, gameAccount, bindUUID string, apiClien
 	}
 	// 已在上游创建正式订单的失败订单禁止自动重发，避免重复发货。
 	if orderStatus == model.OrderStatusShipFailed && deliverySubmittedUpstream(order) {
-		return nil, newDeliveryHTTPError(http.StatusConflict, "该订单已提交上游，为避免重复发货不能直接重试，请先在上游确认订单状态或联系平台处理")
+		return nil, newDeliveryHTTPError(http.StatusConflict, "该订单已进入发货流程，为避免重复发货不能直接重试，请稍后查询订单状态或联系平台处理")
 	}
 	if !info.CanShip {
 		reason := info.CannotShipReason
@@ -351,10 +351,10 @@ func (s *DeliveryService) submit(orderNo, gameAccount, bindUUID string, apiClien
 		"upstream_order":       upstreamOrder,
 	})
 	nextStatus := model.OrderStatusDelivering
-	message := "已提交上游发货，等待发货结果回传"
+	message := "已提交发货，等待发货结果回传"
 	if upstreamDeliverySucceeded(upstreamOrder) {
 		nextStatus = model.OrderStatusDelivered
-		message = "上游已返回发货成功"
+		message = "发货已完成"
 	}
 	updated, err := s.fulfillment.UpdateFulfillment(FulfillmentUpdateInput{
 		MerchantID:      order.MerchantID,
@@ -533,7 +533,7 @@ func (s *DeliveryService) buildDeliveryState(openOrder *OpenOrderQuery, order *m
 		goodID = deliveryGoodID(s.channel, openOrder.Product.SKU)
 		if goodID == "" {
 			canShip = false
-			reason = "未找到对应的上游商品配置"
+			reason = "未找到对应的商品发货配置"
 		}
 	}
 	if requireCanShip && !canShip {
@@ -743,7 +743,7 @@ func (s *DeliveryService) prepareOrder(orderNo string, requireCanShip bool, auth
 		goodID = deliveryGoodID(s.channel, openOrder.Product.SKU)
 		if goodID == "" {
 			canShip = false
-			reason = "未找到对应的上游商品配置"
+			reason = "未找到对应的商品发货配置"
 		}
 	}
 	if requireCanShip && !canShip {
@@ -892,11 +892,11 @@ func (s *DeliveryService) createOrderQueue(goodID, orderNo string) (string, erro
 		return "", err
 	}
 	if len(out.Orders) == 0 {
-		return "", errors.New("上游未返回队列订单")
+		return "", errors.New("发货服务未返回队列订单")
 	}
 	orderID := firstNonEmpty(stringFromMap(out.Orders[0], "_id"), stringFromMap(out.Orders[0], "id"))
 	if orderID == "" {
-		return "", errors.New("上游未返回队列订单 ID")
+		return "", errors.New("发货服务未返回队列订单 ID")
 	}
 	return orderID, nil
 }
@@ -945,7 +945,7 @@ func (s *DeliveryService) signProxy(path, method string, data interface{}, out i
 	req.Header.Set("Content-Type", "application/json")
 	resp, err := s.httpClient.Do(req)
 	if err != nil {
-		return fmt.Errorf("上游请求失败：%w", err)
+		return fmt.Errorf("发货服务请求失败：%w", err)
 	}
 	defer resp.Body.Close()
 	body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
@@ -955,19 +955,19 @@ func (s *DeliveryService) signProxy(path, method string, data interface{}, out i
 		Data    json.RawMessage `json:"data"`
 	}
 	if err := json.Unmarshal(body, &envelope); err != nil {
-		return fmt.Errorf("上游响应无法解析：%s", truncateDeliveryText(string(body)))
+		return fmt.Errorf("发货服务响应无法解析：%s", truncateDeliveryText(string(body)))
 	}
 	if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices || !isZeroCode(envelope.Code) {
 		if envelope.Message != "" {
 			return errors.New(envelope.Message)
 		}
-		return fmt.Errorf("上游请求失败：HTTP %d", resp.StatusCode)
+		return fmt.Errorf("发货服务请求失败：HTTP %d", resp.StatusCode)
 	}
 	if out == nil || len(envelope.Data) == 0 || string(envelope.Data) == "null" {
 		return nil
 	}
 	if err := json.Unmarshal(envelope.Data, out); err != nil {
-		return fmt.Errorf("上游数据无法解析：%w", err)
+		return fmt.Errorf("发货服务数据无法解析：%w", err)
 	}
 	return nil
 }