skill-audit's Description dimension implied Vale's DescriptionOpener
alert fully covers imperative-phrasing checks, but that rule only
matches the literal "This skill..." pattern. agent-audit kept its
equivalent manual "does the description open with a verb" fallback
bullet; skill-audit's got dropped when Vale wiring landed in #85,
leaving other non-imperative openers (gerunds, passive phrasing) to
sail through unflagged. Restore the parallel check.