Two harness drivers (model A per-command auth, model B persistent auth-once)
run across the real release cube-server to settle the "auth-each-time had ~0%
errors" memory. Conclusion: error rate is driven by the slow `audit` op /
3s socket cap, NOT the auth model — with audit removed, model A hits 94.81%
and model B 100%. Adds docs/stress-comparison-20260811.md §5 and the two
reusable harness scripts under tools/.
