refactor: primitives now use Core.Math for math

Engine.Core/Primitives/Vector2D.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core;
 
 /// <summary>
@@ -316,7 +314,7 @@ public readonly struct Vector2D(float x, float y)
     /// Generates a hash code for the <see cref="Vector2D"/>.
     /// </summary>
     /// <returns>A hash code for the <see cref="Vector2D"/>.</returns>
-    public override int GetHashCode() => HashCode.Combine(X, Y);
+    public override int GetHashCode() => System.HashCode.Combine(X, Y);
 }
 
 /// <summary>