feat: create window client app

Client/Domain/Service/HandlerInterface.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Client.Domain.DTO;
+using Client.Domain.Enums;
+
+namespace Client.Domain.Service
+{
+    public interface HandlerInterface
+    {
+        void Update(MessageOperationEnum operation, string content);
+    }
+}