This paper addresses the survival‑critical risks posed by cryptographically relevant quantum computers (CRQCs) and the urgent need for post‑quantum cryptography (PQC) migration. It provides a forensic framework for boards and regulators to assess exposure, prioritize migration pathways, and enforce accountability. The analysis covers the collapse of RSA/ECC under Shor’s Algorithm, the harvest‑now‑decrypt‑later threat, and the solvency implications for data‑holding institutions. A governance mandate is outlined, linking PQC migration to board‑level fiduciary duties, regulatory resilience, and strategic survival KPIs. The paper concludes with a structured roadmap for PQC adoption, budget allocation, and audit‑grade enforcement, positioning quantum risk as a board accountability issue rather than a technical option.