Build 21083866

This quality of life upgrade is for long-term stability:

• Upgraded game engine to Unity 6.3, to keep the game current

• Removed unused packages and game assets, updated necessary packages (e.g. for camera controls) to optimize game build

• Upgraded to use Unity's new input system for improved controls

This makes NinjaThea more maintainable and more accessible. As always, thanks for playing!