Remove legacy GamePlaying states and consolidate all gameplay logic
to use the GameLevelPlaying state system. This simplifies state
management by eliminating duplicate code paths and ensures consistent
behavior across all game modes including Free Play.
- Add Level model with constraints, objectives, and star ratings
- Create LevelService for loading levels from JSON configuration
- Implement LevelSelectionScreen with visual progress tracking
- Update GameBloc to handle level-based gameplay
- Add 10 predefined levels with varying difficulty and objectives
- Integrate level progression system into game flow