feat(discount): add InStock filter to discount product queries and mappings

- Introduced InStock property to GetDiscountProductsQuery and GetCustomerProductsByFilterQuery for filtering based on product availability.
- Updated query handlers to apply InStock filtering logic in both discount and customer product queries.
- Enhanced mapping configurations to include InStock in the response DTOs.
- Bumped Protobuf project version to reflect the addition of new features.

src/CMSMicroservice.Application/DiscountShopCQ/Queries/GetDiscountProducts/GetDiscountProductsQuery.cs

@@ -8,6 +8,10 @@ public class GetDiscountProductsQuery : IRequest<GetDiscountProductsResponseDto>
     public PaginationState? PaginationQuery { get; set; }
     public long? CategoryId { get; set; }
     public string? SearchTerm { get; set; }
+    /// <summary>
+    /// true = فقط موجود (RemainingCount &gt; 0)، false = فقط ناموجود
+    /// </summary>
+    public bool? InStock { get; set; }
     public bool? IsActive { get; set; }
     public int? MinPrice { get; set; }
     public int? MaxPrice { get; set; }

src/CMSMicroservice.Application/DiscountShopCQ/Queries/GetDiscountProducts/GetDiscountProductsQueryHandler.cs

@@ -42,6 +42,11 @@ public class GetDiscountProductsQueryHandler : IRequestHandler<GetDiscountProduc
             query = query.Where(p => p.IsActive == request.IsActive.Value);
         }
 
+        if (request.InStock == true)
+            query = query.Where(p => p.RemainingCount > 0);
+        else if (request.InStock == false)
+            query = query.Where(p => p.RemainingCount <= 0);
+
         if (request.MinPrice.HasValue)
         {
             query = query.Where(p => p.Price >= request.MinPrice.Value);