Forgot unversioned xd

SVSim.EmulatedEntrypoint/Models/Dtos/Common/EmptyResponse.cs

@@ -0,0 +1,14 @@
+using MessagePack;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.Common;
+
+/// <summary>
+/// Shared empty response. Used for endpoints whose spec mock is `"data": {}`
+/// (set_deck_redis, update_order, delete_deck_list, etc.). Includes a sentinel
+/// nullable field so MessagePack-CSharp emits a string-keyed empty map cleanly.
+/// </summary>
+[MessagePackObject]
+public class EmptyResponse
+{
+    [Key("_")] public object? Reserved { get; set; }
+}