CI: replace flake8 and isort in favor of ruff

[fariss]

This is not high priority by any means, but I think it is possible to replace flake8 and isort in favor of ruff (we use all 3). The ruff team maintains rule parity with all flake8 plugins used here.

[MrRogueKnight]

Hi! I'd like to work on this issue.
My plan is to replace flake8 and isort with ruff in the CI workflow, keeping the migration minimal and aligned with the current linting rules.
Please let me know if you have any preferences or specific rules you'd like preserved before I proceed.