Persists welcome-wizard Step 1/2/3 progress for self-serve signup Phase 2.
PATCH validates step cannot decrease, ignores `data` on action="skip", and
is idempotent on re-PATCH of the same step. POST /users/me/onboarding-dismiss-rest
backs the wizard's "Skip the rest" button.
Both routes added to _EMAIL_VERIFICATION_ALLOWLIST and _SUBSCRIPTION_GUARD_ALLOWLIST
so the wizard runs before email verification and during the trial. 4 integration
tests cover field writes, skip semantics, decrease guard, and dismiss-rest.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
