优化：已交付订单保留复制/打开发货链接，去掉作废操作

- 已交付订单仍可复用未过期链接查看兑换结果，但不再生成/续期新链接
- 商户后台已交付订单仅显示复制/打开，已作废/已过期单独标识
- 发货中/已取消订单不展示链接操作，避免无效按钮

backend/internal/service/delivery.go

@@ -617,7 +617,7 @@ func (s *DeliveryService) GetOrCreateDeliveryLink(merchantID uint, orderNo, requ
 	if err != nil {
 		return nil, err
 	}
-	// 订单已取消后禁止获取发货链接（含复用未过期链接的路径），与 authorizeDeliveryLink 保持一致。
+	// 已取消订单即使存在未过期链接也不再发放（买家侧授权同样拦截已取消订单）。
 	if normalizeOrderStatus(order) == model.OrderStatusCancelled {
 		return nil, newDeliveryHTTPError(http.StatusBadRequest, "订单已取消，无法获取发货链接")
 	}
@@ -625,9 +625,11 @@ func (s *DeliveryService) GetOrCreateDeliveryLink(merchantID uint, orderNo, requ
 	if order.DeliveryLinkRevokedAt != nil {
 		return nil, newDeliveryHTTPError(http.StatusForbidden, "发货链接已作废")
 	}
+	// 复用未过期链接：已交付/发货中订单也允许查看兑换结果或进度，仅停止发放新链接。
 	if order.DeliveryLinkExpiresAt != nil && order.DeliveryLinkExpiresAt.After(now) {
 		return s.buildDeliveryLinkResult(order.OrderNo, order.DeliveryLinkExpiresAt.UTC().Truncate(time.Second), requestBaseURL), nil
 	}
+	// 仅待发货（含可重试的发货失败）订单能生成或续期新链接。
 	canShip, reason := CanFulfill(order)
 	if !canShip {
 		if reason == "" {

backend/internal/service/delivery_test.go

@@ -116,6 +116,69 @@ func TestDeliveryLinkRejectedAfterOrderCancelled(t *testing.T) {
 	}
 }
 
+func TestDeliveryLinkAfterDeliveredReusesButNeverGenerates(t *testing.T) {
+	db := newServiceTestDB(t)
+	merchantID, product := seedFulfillmentMerchant(t, db, "delivery-done", 5000, 5, 100)
+	fulfillmentSvc := NewFulfillmentService(db, nil)
+	deliverySvc := NewDeliveryService(fulfillmentSvc, "https://bff.example", "dlc", "https://shop.example", "link-secret", 60)
+
+	created, err := fulfillmentSvc.CreateOrder(CreateFulfillmentOrderInput{
+		MerchantID:    merchantID,
+		APIClientID:   1,
+		ClientOrderNo: "delivery-done-001",
+		SKU:           product.SKU,
+	})
+	if err != nil {
+		t.Fatalf("create order: %v", err)
+	}
+	link, err := deliverySvc.GetOrCreateDeliveryLink(merchantID, created.Order.OrderNo, "https://shop.example")
+	if err != nil {
+		t.Fatalf("get delivery link: %v", err)
+	}
+	if _, err := fulfillmentSvc.UpdateFulfillment(FulfillmentUpdateInput{
+		MerchantID:  merchantID,
+		APIClientID: 1,
+		OrderNo:     created.Order.OrderNo,
+		Status:      model.OrderStatusDelivered,
+	}); err != nil {
+		t.Fatalf("mark delivered: %v", err)
+	}
+	// 已交付订单仍可复用未过期的既有链接（查看兑换结果），但不会生成新链接。
+	reused, err := deliverySvc.GetOrCreateDeliveryLink(merchantID, created.Order.OrderNo, "https://shop.example")
+	if err != nil {
+		t.Fatalf("delivered order should reuse existing link: %v", err)
+	}
+	if reused.DeliveryURL != link.DeliveryURL || reused.Exp != link.Exp {
+		t.Fatalf("reused link should match original, got %+v", reused)
+	}
+	// 买家侧仍可通过既有链接只读查看交付结果。
+	if _, err := deliverySvc.GetOrder(created.Order.OrderNo, DeliveryLinkAuth{Exp: link.Exp, Sign: link.Sign}); err != nil {
+		t.Fatalf("delivered order link should stay readable for the buyer: %v", err)
+	}
+
+	// 从未生成过链接的已交付订单，不能再获取新链接。
+	second, err := fulfillmentSvc.CreateOrder(CreateFulfillmentOrderInput{
+		MerchantID:    merchantID,
+		APIClientID:   1,
+		ClientOrderNo: "delivery-done-002",
+		SKU:           product.SKU,
+	})
+	if err != nil {
+		t.Fatalf("create second order: %v", err)
+	}
+	if _, err := fulfillmentSvc.UpdateFulfillment(FulfillmentUpdateInput{
+		MerchantID:  merchantID,
+		APIClientID: 1,
+		OrderNo:     second.Order.OrderNo,
+		Status:      model.OrderStatusDelivered,
+	}); err != nil {
+		t.Fatalf("mark second delivered: %v", err)
+	}
+	if _, err := deliverySvc.GetOrCreateDeliveryLink(merchantID, second.Order.OrderNo, "https://shop.example"); err == nil {
+		t.Fatalf("delivered order without existing link should not generate a new one")
+	}
+}
+
 func TestDeliveryGoodIDIncludesMedalAndCoinProducts(t *testing.T) {
 	cases := map[string]string{
 		"honor_medal_x2":  "682ef39ca8f40c4234c59f45",

frontend/src/pages/merchantCenterTabs.tsx

@@ -260,9 +260,29 @@ export function OrdersTab({
       key: 'delivery_link',
       width: 160,
       render: (_, record) => {
+        // 非可发货状态不再展示链接作废等操作；已交付订单保留复制/打开，便于查看兑换结果。
         if (record.order_status === 'cancelled') {
           return <Typography.Text type="secondary">订单已取消</Typography.Text>
         }
+        if (record.order_status === 'delivering') {
+          return <Typography.Text type="secondary">发货中</Typography.Text>
+        }
+        if (record.order_status === 'delivered') {
+          if (record.delivery_link_revoked_at) {
+            return <Tag color="red">已作废</Tag>
+          }
+          const expired = !record.delivery_link_expires_at
+            || new Date(record.delivery_link_expires_at).getTime() < Date.now()
+          if (expired) {
+            return <Typography.Text type="secondary">已过期</Typography.Text>
+          }
+          return (
+            <Space size={4} wrap>
+              <Button type="link" size="small" onClick={() => onCopyLink(record.order_no)}>复制</Button>
+              <Button type="link" size="small" onClick={() => onOpenLink(record.order_no)}>打开</Button>
+            </Space>
+          )
+        }
         if (record.delivery_link_revoked_at) {
           return <Button type="link" size="small" onClick={() => onRestoreLink(record.order_no)}>恢复链接</Button>
         }