8 migrated datasets still hold audit_annotations.yml entries; nothing enforces the manifest-or-annotation rule

[mmcky]

8 migrated datasets still hold audit_annotations.yml entries, and nothing enforces the manifest-or-annotation rule

scripts/audit_annotations.yml's own header rule says migrated datasets (those with lectures/*.yml manifests) do not get entries in datasets: — the manifest is their source of truth. Independent validation for #84 (Phase 1) cross-checked the invariant and found it violated by 8 datasets, all status: repointed in migration.yml and all carrying manifests:

assignat.xlsx · caron.npy · chapter_3.xlsx · dette.xlsx · fig_3.xlsx · longprices.xls · mpd2020.xlsx · nom_balances.npy

The hansen_singleton pair from wave B2′ was retired correctly — this debt is from earlier waves, surfaced by the #84 cross-check.

Why it rots silently: build_audit.py uses an annotation only as a fallback (manifest or annotation) when building descriptions/provenance, so the stale entries are inert at runtime, and no check — including --strict — flags a dataset that has both. A green strict audit therefore says nothing about this invariant.

Two-part fix:

1. Delete the 8 stale datasets: entries (their manifests already carry the information; a quick diff of each entry against its manifest before deletion would catch anything the annotation has that the manifest lost).
2. Add the invariant to build_audit.py --strict: any filename appearing both as a lectures/*.yml manifest and as an audit_annotations.yml datasets: entry is an inconsistency. That makes the header rule enforceable instead of aspirational — the same reasoning as the migration.yml flip test in VALIDATION: independent review of the 2026-08-13 Track B migration work (waves B1' and B2') #84 §5: a rule that cannot go red is not evidence when green.

Two harmless near-misses noted for completeness, requiring no action: NEWQDATA.csv is mentioned inside an api: note and fig_3.xlsx inside a committed_unreferenced note — prose mentions, not datasets: entries.