#90 Comprehensive mission-critical audit, review and improvement proposal for Futex HITL

EARS SPEC: - The audit shall falsify all claims in SPEC_V2.md, PRODUCTION_READINESS.md, and SPECS/ through live reproduction. - The audit shall examine concurrency/state-machine integrity, tenant isolation, security surface, worker durability, and integration correctness. - The audit shall test every guard in both directions (block AND release). - The audit shall persist all probes in audit/evaluations/ as a reusable harness. - The audit shall propose concrete improvements ranked by blast radius. - If any finding is confirmed, then the audit shall provide the smallest correct fix. - If any finding cannot be reproduced live, then the audit shall mark it SUSPECTED with reasoning.