Refactor ConsumeAmmoCost to use readonly field for ammoId and improve Entity struct equality methods

GameCore/ECS/Entity.cs

@@ -1,11 +1,23 @@
+using System.Diagnostics.CodeAnalysis;
+
 namespace GameCore.ECS;
 
 /// <summary>
-/// Represents a unique object in the game world.
-/// It's a simple struct containing an ID to keep it lightweight.
-/// All data associated with an Entity is stored in Components.
+///     Represents a unique object in the game world.
+///     It's a simple struct containing an ID to keep it lightweight.
+///     All data associated with an Entity is stored in Components.
 /// </summary>
 public readonly struct Entity(int id)
 {
     public readonly int Id = id;
+
+    public override bool Equals([NotNullWhen(true)] object? obj)
+    {
+        return base.Equals(obj);
+    }
+
+    public override int GetHashCode()
+    {
+        return Id.GetHashCode();
+    }
 }