lint repo with `ruff` -- `pre-commit`

[jGaboardi]

ensure spreg is actually being linted with ruff via .pre-commit

[jGaboardi]

Preliminary lint check found 1361 errors. I will likely be tackling the linting across multiple PRs.

[jGaboardi]

@pedrovma Considering https://github.com/pysal/spreg/pull/156#issuecomment-2325161757:

1. Is this something you are interested in?
2. If yes, would it help for me to put in 1 PR per file to ease the merging into the private branch?

In my opinion, this is something that spreg desperately needs to ensure maintainability into the future[^1][^2]

[^1]: currently 1533 warnings in dev [^2]: currently 1361 items that need attention for linting

[pedrovma]

Hi @jGaboardi . I think individual PRs would be too much work. Luc and I are just finishing some tests and formatting for the release of version 1.7. It will be released by the end of this month. After the release, we can freeze the development in the private repo so you can work freely on the linting here. What do you think?

Many thanks.

[jGaboardi]

Sure. That works.