fix(regular-store): deduct inventory and restore on cancel

- UserOrderService.SubmitShopBuyOrder: inject IInventoryService; validate
  available stock per item before any financial operation; call ConfirmSaleAsync
  and increment Product.SaleCount after order is persisted.
- CancelOrderByAdminCommandHandler: inject IInventoryService; include
  FactorDetails in query; call ProcessReturnAsync for each item so stock
  is restored when an order is cancelled by admin.

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

src/CMSMicroservice.WebApi/Services/UserOrderService.cs

@@ -29,12 +29,14 @@ public class UserOrderService : UserOrderContract.UserOrderContractBase
     private readonly ISender _sender;
     private readonly IApplicationDbContext _context;
     private readonly ICurrentUserService _currentUserService;
+    private readonly IInventoryService _inventoryService;
 
-    public UserOrderService(ISender sender, IApplicationDbContext context, ICurrentUserService currentUserService)
+    public UserOrderService(ISender sender, IApplicationDbContext context, ICurrentUserService currentUserService, IInventoryService inventoryService)
     {
         _sender = sender;
         _context = context;
         _currentUserService = currentUserService;
+        _inventoryService = inventoryService;
     }
     [RequiresPermission(PermissionNames.OrdersCreate)]
     public override async Task<CreateNewUserOrderResponse> CreateNewUserOrder(CreateNewUserOrderRequest request, ServerCallContext context)
@@ -285,6 +287,18 @@ public class UserOrderService : UserOrderContract.UserOrderContractBase
             throw new RpcException(new Status(StatusCode.InvalidArgument, 
                 $"مبلغ نامعتبر است. محاسبه شده: {totalAmount}, دریافتی: {request.TotalAmount}"));
         }
+
+        // Validate stock availability for all cart items before any financial operation
+        foreach (var cartItem in cartItems)
+        {
+            var available = await _inventoryService.GetAvailableQuantityAsync(
+                cartItem.ProductId, ProductType.RegularProduct, ct: context.CancellationToken);
+            if (available < cartItem.Count)
+            {
+                throw new RpcException(new Status(StatusCode.FailedPrecondition,
+                    $"موجودی «{cartItem.Product.Title}» کافی نیست. موجود: {available}، درخواستی: {cartItem.Count}"));
+            }
+        }
         
         // Get user's wallet
         var wallet = await _context.UserWallets
@@ -461,6 +475,18 @@ public class UserOrderService : UserOrderContract.UserOrderContractBase
             cartItem.IsDeleted = true;
         }
         
+        await _context.SaveChangesAsync(context.CancellationToken);
+
+        // Deduct inventory and update SaleCount for each purchased item
+        foreach (var cartItem in cartItems)
+        {
+            await _inventoryService.ConfirmSaleAsync(
+                cartItem.ProductId, ProductType.RegularProduct,
+                cartItem.Count, order.Id, context.CancellationToken);
+
+            cartItem.Product.SaleCount += cartItem.Count;
+        }
+
         await _context.SaveChangesAsync(context.CancellationToken);
         
         return new SubmitShopBuyOrderResponse