Pre-audit review: read the contracts and the crypto

Before the external audit, more eyes help. Useful places to look:

• contracts/v3/core/MaktubCore.sol: timer, check-in and execution, including the 2-day permissionless backstop
• contracts/v3/core/MaktubFlash.sol
• Warden node/src/eval.rs: the evaluator that decides when a key is released
• The cross-language reading-key vectors in maktub/vectors/

Report security problems privately, following SECURITY.md. Use this issue for questions, notes on what you've reviewed, and non-security findings.