Replaces os.path/open()/os.stat()/os.chmod() calls with their Path
method equivalents across src, tests, misc, and bin, wrapping str
variables in Path(...) where they must stay str for other uses (e.g.
subprocess argv, CLI-arg formatting). helpers.safe_symlink() now
decodes StrOrBytesPath to a str Path via os.fsdecode() upfront, same
pattern already used elsewhere for the str|bytes union.
prek runs local hooks as plain execs against tools uv already provisions,
so ruff/mypy can never drift from the versions/config uv.lock pins
elsewhere and CI needs no separate hook-cache download.
- Add ruff and prek to the uv dev dependency group (ruff wasn't a
uv-managed dependency before; pre-commit silently vendored its own).
- Replace .pre-commit-config.yaml with prek.toml: keep the
pre-commit-hooks repo for generic file checks, convert ruff-format/
ruff-check to local `uv run ruff ...` hooks, and add a local mypy
hook that reports but never fails (87 pre-existing errors need a
separate cleanup before it can be made blocking).
- Add a `lint` job to CI that runs `prek run --all-files` and gate the
OS/Python test matrix on it so lint issues fail fast.
- Fix the ruff debt (format + lint) uncovered by actually running it,
since it was small and mechanical, so the new CI gate starts green.
James R. Barlow