The regression test from #290 walks the filesystem via Path.rglob, so
docs/plans/*.md files (gitignored, created by internal planning) trip
the assertion on any dev machine that has run ce:plan in this repo.
Fresh clones and CI never see them, but local runs fail.
Adding docs to skip_dirs keeps the guard narrow to first-class source
files while letting internal planning docs reference old paths
verbatim.
Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Claire Novotny