feat: added entity converter

Engine.Serialization/Converters/EntityReference.cs

@@ -0,0 +1,12 @@
+using Syntriax.Engine.Core;
+
+namespace Syntriax.Engine.Serialization;
+
+public class EntityReference
+{
+    public string Id { get; set; } = string.Empty;
+    public TypeContainer TypeContainer { get; set; } = new();
+
+    public EntityReference() { }
+    public EntityReference(IEntity entity) { TypeContainer = new(entity); Id = entity.Id; }
+}