useActionForm has zero Mars consumers - decide adopt vs leave

MARS-419 finding (coder-mars-cc, 2026-07-12): useActionForm (src/hooks/use-action-form.ts, MARS-408 primitive) has zero Mars consumers; forms hand-roll useToast+setError instead, which produced the raw-text-red bypasses closed in c26b07c. Cross-project decision needed: (a) adopt useActionForm across Mars mutation forms so required-field+!ok surfacing is structural, or (b) leave as-is now that the friction lint (extended w/ text-red- in c26b07c) mechanically catches uncaptured surfaces. Fleet-authored/vendored primitive - no unilateral mass-migrate.