The pre-commit job failed with
/root/.local/bin/pre-commit: No such file or directory
even though `pipx install pre-commit` succeeded: `pipx install` writes the
app to PIPX_BIN_DIR, and the runner image no longer uses ~/.local/bin for
it. Run the binary from PATH when pipx put it there, and fall back to
`pipx run pre-commit` otherwise, so the hook still runs regardless of
where pipx exposes its apps.