feat: add vendorId to order detail response for permission check

cfc-backend/src/main/java/com/etotem/cfc/dto/ProductOrderDTO.java

@@ -57,6 +57,8 @@ public class ProductOrderDTO {
     private Date fulfillConfirmedAt;
     private Date receivedAt;
 
+    private Long vendorId;
+
     public static ProductOrderDTO from(ProductOrder o) {
         if (o == null) return null;
         ProductOrderDTO d = new ProductOrderDTO();

cfc-backend/src/main/java/com/etotem/cfc/service/ProductOrderService.java

@@ -1129,7 +1129,11 @@ public class ProductOrderService {
         if (!isBuyer && !isVendor) {
             return Result.error("无权查看");
         }
-        return Result.success(ProductOrderDTO.from(order));
+        ProductOrderDTO dto = ProductOrderDTO.from(order);
+        if (product != null) {
+            dto.setVendorId(product.getVendorId());
+        }
+        return Result.success(dto);
     }
 
     public Result<List<ProductOrderDTO>> vendorOrders(Long vendorId, String status) {