- Add `set_text()`, `set_track_image()`, `set_thumb_image()` methods.
- Include label rendering and auto-scaling based on slider dimensions.
- Replace static `THUMB_WIDTH` with dynamic thumb sizing.
- Add slider thumb and track texture assets.
- Implement MainMenuScene with a "Start Game" button that pushes the WorldScene.
- Extend Button class with background/foreground, hover detection, and size queries.
- Add virtual width/height and event handlers to Widget base class.
- Update WorldUIManager to propagate mouse move events.
- Adjust Window mouse mode based on game running state.