fix(order): include payment_method in order list API response

OrderSummaryDto and ListOrdersByShop Dapper query were missing the
payment_method column, causing the POS history tab to always show
"Chưa thanh toán" (Unpaid) even for completed/paid orders.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

services/order-service-net/src/OrderService.API/Application/DTOs/OrderDtos.cs

@@ -49,6 +49,7 @@ public record OrderSummaryDto
     public Guid? TableId { get; init; }
     public string Status { get; init; } = string.Empty;
     public decimal TotalAmount { get; init; }
+    public string? PaymentMethod { get; init; }
     public long ItemCount { get; init; }
     public DateTime CreatedAt { get; init; }
 }

services/order-service-net/src/OrderService.API/Application/Queries/ListOrdersByShopQueryHandler.cs

@@ -40,13 +40,14 @@ public class ListOrdersByShopQueryHandler : IRequestHandler<ListOrdersByShopQuer
         // EN: Get paged data
         // VI: Lấy dữ liệu phân trang
         var sql = $@"
-            SELECT 
+            SELECT
                 o.id AS Id,
                 o.shop_id AS ShopId,
                 o.customer_id AS CustomerId,
                 o.table_id AS TableId,
                 os.name AS Status,
                 o.total_amount AS TotalAmount,
+                o.payment_method AS PaymentMethod,
                 o.created_at AS CreatedAt,
                 (SELECT COUNT(*) FROM order_items WHERE order_id = o.id) AS ItemCount
             FROM orders o