refactor!: Identifiable interface extracted from IEntity

Engine.Core/Serialization/IdentifiableRegistry.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+
+namespace Engine.Core.Serialization;
+
+public class IdentifiableRegistry
+{
+    public Event<IdentifiableRegistry, EntityRegisteredArguments> OnEntityRegistered = null!;
+
+    private readonly Dictionary<string, Action<IIdentifiable>?> assignCallbacks = [];
+    private readonly Dictionary<string, IIdentifiable> registeredEntities = [];
+    public IReadOnlyDictionary<string, IIdentifiable> RegisteredEntities => registeredEntities;
+
+    public void Add(IIdentifiable identifiable)
+    {
+        if (registeredEntities.TryAdd(identifiable.Id, identifiable))
+            OnEntityRegistered?.Invoke(this, new(identifiable));
+    }
+
+    public void QueueAssign(string id, Action<IIdentifiable> setMethod)
+    {
+        assignCallbacks.TryAdd(id, null);
+        assignCallbacks[id] = assignCallbacks[id] + setMethod;
+    }
+
+    public void AssignAll()
+    {
+        foreach ((string id, Action<IIdentifiable>? action) in assignCallbacks)
+            action?.Invoke(registeredEntities[id]);
+    }
+
+    public void Reset()
+    {
+        assignCallbacks.Clear();
+        registeredEntities.Clear();
+    }
+
+    public readonly record struct EntityRegisteredArguments(IIdentifiable Entity);
+}