Modern B2B SaaS procurement and frontend engineering share a common blind spot: silent state transitions . On the procurement side, SaaS billing systems use silent seat promotions ("zombie seats") and 30-to-60-day contractual auto-renewal cutoff windows to inflate annual renewals by 25% to 40%. On the engineering side, frontend teams frequently ship broken billing, rate-limit, and quota-upgrade modals because testing HTTP 402 Payment Required or 429 Too Many Requests states against live pro...