- Convert from function-based to class-based architecture
- Create GameObject base class with common functionality (position, collision, scene management)
- Implement Player, Coin, and Obstacle classes extending GameObject
- Add Game class to manage game lifecycle and state
- Fix shadow rendering by configuring directional light shadow camera bounds
- Fix player collision to prevent sinking below ground (horizontal push only)
- Improve code organization and maintainability with OOP principles
