feat: 查价结果返回销售产品说明

OrderPriceCheck 输出增加 ProductDescription，供前端报价卡展示线路简要说明。

Co-authored-by: Cursor <cursoragent@cursor.com>

src/Oms.Application/Dtos/Orders/OrderPriceCheckOutput.cs

@@ -57,6 +57,11 @@ public class OrderPriceCheckOutput
     /// </summary>
     public string? ProductGroupName { get; set; }
 
+    /// <summary>
+    /// 产品说明（线路简要说明，对客展示）。
+    /// </summary>
+    public string? ProductDescription { get; set; }
+
     /// <summary>
     /// 体积重量。
     /// </summary>

src/Oms.Application/Services/Orders/OrderService.ParcelQuote.cs

@@ -276,6 +276,9 @@ public partial class OrderService
                             TradeTerms = string.IsNullOrWhiteSpace(product.TradeTerms) ? null : product.TradeTerms.Trim().ToUpperInvariant(),
                             ProductGroup = groupCode,
                             ProductGroupName = groupName,
+                            ProductDescription = string.IsNullOrWhiteSpace(product.ProductDescription)
+                                ? null
+                                : product.ProductDescription.Trim(),
                             VolumetricWeight = quote.VolumetricWeight,
                             ChargeableWeight = quote.ChargeableWeight,
                             CostFormula = summary.CostFormula,