Refactors GJK tetrahedron handling

Updates the `handle_tetrahedron` function to use const references for simplex points, improving efficiency and readability.

Corrects a potential bug where the `simplex` variable wasn't being correctly updated when recursively calling `handle_triangle`.

Also, const-qualifies `point_to_same_direction` for better safety.

include/omath/utility/color.hpp

@@ -9,7 +9,7 @@
 
 namespace omath
 {
-    struct Hsv
+    struct Hsv final
     {
         float hue{};
         float saturation{};