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/linear_algebra/vector3.hpp

@@ -217,7 +217,7 @@ namespace omath
         }
 
         [[nodiscard]]
-        bool point_to_same_direction(const Vector3& other)
+        bool point_to_same_direction(const Vector3& other) const
         {
             return dot(other) > static_cast<Type>(0);
         }