Live diagnosis experiment PRD

• R1 (P0): Every refund must call verify_refund_eligibility before process_refund; a refund without the check is a policy violation.
• R2 (P1): check_stock must complete within 250 ms. On origin timeout the orchestrator must use the degraded cache route; it must not simply fail.
• R3 (P1): Regression cases must cite the source trajectory ID and the exact observed turn where the violation is visible.