record blocked legacy model provenance migration

docs/CODEX_EXECUTION_LOG.md

@@ -12498,3 +12498,33 @@ Open:
 - The active model remains review-required and Kempen-scoped. The export gate
   prevents overstated results; it does not replace the missing independent,
   human-reviewed national accuracy corpus or improve model weights by itself.
+
+## 2026-08-09 - Reviewedexp6 provenance migration audit
+
+### Inspected
+
+- Recovered and checksummed the original challenger weights, training summary,
+  Ultralytics arguments, results, dataset YAML, 252-tile/79,192-label summary
+  and legacy dataset-quality audit.
+- Reproduced the recorded seed `0`, deterministic request, CPU device, twenty
+  epochs, active base-model hash and train/validation counts.
+- Ran the current human-review eligibility validator against the retained
+  audit; it failed on missing accepted review evidence, manifest immutability,
+  spatial-leakage status and incomplete review state.
+
+### Decision
+
+- Refused to invent the absent historical training commit, container digest,
+  runtime receipt, corpus/label/split manifests, reviewer decisions or source
+  registry UUIDs.
+- Created no runtime sidecar, database provenance row or production model
+  activation. The active scoped model and healthy GPU runtime remain unchanged.
+- Retained the complete fail-closed audit under
+  `artifacts/evidence/accuracy/model-training/20260809-reviewedexp6-provenance-migration-audit.json`.
+
+### Required next gate
+
+- Complete P2-00 through P2-07 and the governed Phase-4 blockers, obtain real
+  representative human review, freeze a new independent corpus and only then
+  train a pre-registered GPU candidate with provenance captured from process
+  start. The legacy checkpoint cannot be made compliant retroactively.