Mainnet Readiness

See `../MAINNET_READINESS.md` for the authoritative checklist.

Short version: KAURAX is not ready for mainnet, and is not close. The blocking items are, in order:

1. No fault-proof system — output roots are trusted (threat-model.md T1).
2. No audits of any component.
3. Single sequencer with no failover and no forced-exit hatch.
4. Every privileged role is a single EOA; no multisig, no timelock.
5. Unbatched blocks are not durably persisted.
6. The testnet profile has been configured but never operated.