- Introduced a new Goal class with methods to manage goal achievement status.
- Enhanced the Goals class to support iteration and length retrieval.
- Updated AI implementations (BarbariansAI, EnemyAI, NatureAI, PlayerAI) to use forward references for Player type.
- Added a Vision class to manage visibility of tiles, units, cities, resources, improvements, and terrain.
- Implemented memory management with a new Memory class and a Memories container.
- Created a BarbarianLion unit class for nature AI interactions.
- Updated player management to include vision and memory functionalities.
- Enhanced UI components to display player information and interactions.
- Added new signals for player info display in the UI.
- Refactored unit spawning logic to improve clarity and functionality.

Signed-off-by: Scarlett Samantha Verheul <scarlett.verheul@gmail.com>