Critical: macOS BSD sed does not support \s character class.
The two substitutions in the version-bump step silently no-oped, the
grep fail-fast guard caught it (no remote damage), but release.sh
couldn't complete. Using POSIX [[:space:]] works on both BSD and GNU sed.
Also: extend test_git_archive_excludes_dev_files to cover .phpunit.result.cache,
.beads/, .claude/, dist/, .DS_Store — the test now fully enforces .gitattributes
export-ignore invariant.