- Add new Engine.AI project referenced by the App.
- Define JSON command model: spawn_model, set_transform, delete_entity, list_entities.
- Implement AiCommandProcessor with System.Text.Json and custom Vector3/Quaternion converters.
- Wire processor into Program.cs; demo commands spawn and move a second cube.
- AI commands are executed against the live Flecs world and visible in the next frame.
