- Window singleton with properties (resolution, fullscreen, vsync, title)
- OOP Scene support with lifecycle methods (on_enter, on_exit, on_keypress, update)
- Window resize events trigger scene.on_resize callbacks
- Scene transitions (fade, slide_left/right/up/down) with smooth animations
- Full integration of Python Scene objects with C++ engine
All Phase 5 tasks (#34, #1, #61, #105) completed successfully.
