Development record

A bare `cd -x` (an option word neither shell takes, with no operand) leaves the directory unknown in the guard, but zsh 5.9 enters a directory literally named `-x` when one exists (verified 2026-10-11 with cd and pwd only), so a following `bash s.sh` runs the script there unread. An existing test expects the allow; zsh's -N directory-stack words need care.