feat: add events for drop and chat message

Client/Domain/Events/ChatMessageCreatedEvent.cs

@@ -0,0 +1,20 @@
+using Client.Domain.Entities;
+using Client.Domain.ValueObjects;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Client.Domain.Events
+{
+    public class ChatMessageCreatedEvent : EventInterface
+    {
+        public readonly ChatMessage Message;
+
+        public ChatMessageCreatedEvent(ChatMessage message)
+        {
+            Message = message;
+        }
+    }
+}