The project uses ruff for lint+format, and pyright was redundant and
slow. The previous pyright run surfaced ~30 false positives from running
outside the venv plus 5 real-but-minor typing issues that don't justify
the extra CI minutes on a 0.2.x CLI.
CI now runs only ruff check, ruff format --check, and the import/CLI
smoke matrix on 3.10/3.11/3.12/3.13.