Seed the current gitnexus-review skill into older PR checkouts, force-add
historically gitignored skill paths, accept plugin-qualified Skill ids,
and lock host-unsafe workspaces to review-output.json so a generation can
finish and score. Sandbox cleanup restores owner write bits before delete
because a session that copytrees the locked clone otherwise leaves 0555
trees that rmtree cannot remove.
Co-authored-by: Cursor <cursoragent@cursor.com>