chore: import upstream snapshot with attribution

dotnet/samples/Demos/AgentFrameworkWithAspire/ChatWithAgent.Configuration/OpenAIChatConfig.cs

@@ -0,0 +1,22 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.ComponentModel.DataAnnotations;
+
+namespace ChatWithAgent.Configuration;
+
+/// <summary>
+/// OpenAI chat configuration.
+/// </summary>
+public sealed class OpenAIChatConfig
+{
+    /// <summary>
+    /// Configuration section name.
+    /// </summary>
+    public const string ConfigSectionName = "OpenAIChat";
+
+    /// <summary>
+    /// The name of the chat model.
+    /// </summary>
+    [Required]
+    public string ModelName { get; set; } = string.Empty;
+}