fix(crosscheck): preserve admitted blocking reviews - #337

Summary

• preserve an admitted semantic review when closure evidence is inadmissible
• retain valid sibling updates while failed new-finding evidence becomes a run-scoped suspicion
• persist admitted Azure results before cleanup ambiguity raises a separate tool alarm
• add sanitized legacy fixtures and executable regressions

Parent-failing evidence

• failed new-finding reproduction previously voided the semantic review
• inadmissible closure proof previously voided the semantic review
• the Azure adapter previously rejected the persist_result callback

Validation

• core Crosscheck suite passed
• Azure Crosscheck suite passed
• ledger tests passed
• repository lint passed
• adversarial review found four isolation and persistence gaps; all four were fixed and regression-tested
• all 13 published PR checks passed

Live checkpoint

• target: PR fix(azure): offload detached gate validation privately #327 at 80f1c54
• result: BLOCKING, not UNREVIEWED
• active durable finding: cc-8f48584d092b in claimed-fixed state
• Azure evidence pairs: 1
• model and staging cleanup: complete
• wall clock: 2148.439 seconds

Spend

• declared release checkpoint cost: $0.3374772
• one earlier invocation failed before dispatch because the Azure operator environment was absent; it incurred no spend

No merge requested.