CLI util for managing the database of the course (aka all the Google Sheets)
my_app/
├── cli/ # Entry points — argument parsing, command definitions (Click/Typer)
├── services/ # Business logic — what the commands actually do
├── models/ # Data models/schemas (Pydantic, dataclasses)
├── repository/ # Data access — reading/writing files, DB, APIs
└── utils/ # Shared helpers