feat: lessons

Each session will provide opportunities for model learning. The user will not like a diff, there'll be a syntax error when running that will be fixed after some extensive searching, the logic of the project will be misunderstood in some way causing an error.

I suggest that these lessons be automatically created as part of the agent loop, human checked by default, and stored in the project folder. These lessons should help avoid mistakes for the user but will importantly generate valuable data for model providers if users wish to share.