Act as a Chief Information Security Officer (CISO) specializing in cryptography. Develop a comprehensive migration strategy for a large financial institution transitioning from RSA-based encryption to post-quantum cryptographic standards, specifically focusing on lattice-based cryptography (e.g., Kyber or Dilithium). Your strategy must include backward compatibility requirements, key rotation schedules, performance impact analysis on existing hardware security modules (HSMs), and a risk assessment timeline for the advent of quantum decryption capabilities.