Add customer communication system

LittleShop.Client/Models/Product.cs

@@ -7,7 +7,7 @@ public class Product
     public string? Description { get; set; }
     public decimal Price { get; set; }
     public decimal Weight { get; set; }
-    public string WeightUnit { get; set; } = string.Empty;
+    public int WeightUnit { get; set; }
     public Guid CategoryId { get; set; }
     public string? CategoryName { get; set; }
     public bool IsActive { get; set; }