Automatically detect when uv is being used

Feature

If .venv/bin/python exists in the root of the project (where the pyproject.toml file is), then automatically use it as the python executable with priority over /usr/bin/python.

Pitch

This feature would make uv work out of the box, instead of a user having to figure out that they need to add --python-executable=.venv/bin/python to the mypy command that they run.

Alternative solutions

There could also be a help note if .venv/bin/python exists and mypy cannot find implementations or library stubs for the majority of the imports, that suggests adding --python-executable=.venv/bin/python to the mypy command.

Empieza rastreando la opción existente --python-executable y cómo mypy localiza la raíz del proyecto que contiene pyproject.toml. Comprueba el comportamiento cuando existe .venv/bin/python, incluida su prioridad sobre /usr/bin/python, y añade cobertura para la selección automática; se considera terminado cuando los proyectos de uv funcionan sin la opción adicional.