- Introduce Mesh3D class with vertices, texture, VBO/VAO.
- Replace Object3D struct and textures map in engine with Mesh3D objects.
- Update createObject to load from file path instead of vertex array.
- Adjust cube rendering to use new vertex count.
- Remove debug prints from Texture2D loading.
- Toggle fragment shader color vs texture usage.
Remove unnecessary #include directives from engine.cpp, onCreate.cpp,
and showFps.cpp to reduce compile time and improve readability.
Also delete extraneous blank lines in CMakeLists.txt for cleaner
configuration.
