canSaveCardsForRole(role) in square.ts is the single source of truth for the
save-card product rule (verified_email, admin — never affiliate). All four
predicate sites (account page, UserBookingModal, BookingFlow, TipPayment) were
wrong before, excluding admin and including affiliate. The worst gap was
BookingFlow passing canSaveCards={authStore.isAuthenticated} to the Pay-Early
modal, which let unverified users save cards — it now passes the derived value.
isNonceStale() + NONCE_STALENESS_MS replace the 240s staleness check duplicated
five times, keeping the amount-bound re-tokenization semantics identical.