Add layered system viewer and local coordinates

apps/backend/Simulation/RuntimeModels.cs

@@ -116,6 +116,8 @@ public readonly record struct Vector3(float X, float Y, float Z)
 {
   public static Vector3 Zero => new(0f, 0f, 0f);
 
+  public float LengthSquared() => (X * X) + (Y * Y) + (Z * Z);
+
   public float DistanceTo(Vector3 other)
   {
     var dx = X - other.X;