fix issues

ChatBot.Tests/Models/ChatSessionTests.cs

@@ -359,7 +359,7 @@ public class ChatSessionTests
         var session = new ChatSession();
         session.AddUserMessage("Test", "user");
         var lastUpdated = session.LastUpdatedAt;
-        await Task.Delay(10); // Small delay
+        await Task.Delay(10, CancellationToken.None); // Small delay
 
         // Act
         session.ClearHistory();