test(docs): C-80 — scan ADRs and CICs; three stale paths found and fixed

[Polichinel]

B5. ADRs and CICs were exempt from the deleted-symbol scan. Right in principle — an ADR legitimately records superseded designs, and a scan that fires on history gets deleted (ADR-014 §3) — and far too wide in practice. It is how a CIC came to name a collaborator its class had never called, in six places, for weeks.

The design was chosen by measurement, not argument

candidate check	hits	verdict
path resolution over ADRs	29	not built — inspection showed most were correct history, other repos' files, or paths inside URLs
deleted-symbol list over ADRs	22 (14 in ADR-011 alone)	built, with escapes
deleted-symbol list over CICs	0	built

I built the measurement first and then declined to build the check it argued against. That is the cry-wolf outcome this entry predicted, confirmed before writing code rather than after shipping it.

Three of the hits were real

ADR-013 still cited unfao/historical.py, unfao/wire/ and unfao/wire/source_selection.py — all moved to contract/ by #153. Fixed. Three genuine defects hiding among five markable ones is the ratio that justified turning the scan on.

Two escapes, both declared rather than inferred

Line-scoped legacy-ok for an isolated historical mention; a new file-level <!-- legacy-ok-file: … --> for a document whose subject is a retirement. ADR-011 earned it — it is the decision to remove the runtime mapper, so its subject appears fourteen times, correctly. Marking fourteen lines would be noise pretending to be rigour.

A second guard pins the file-level exemption set to that one document, so a third shows up in a diff rather than becoming a quiet way to silence the check.

A check nothing else could have made

test_a_cic_does_not_name_a_collaborator_its_class_never_calls asserts that a class a CIC names is actually referenced by the class it documents. That is the GaulLookupEnricher failure — which no path check and no symbol list would have caught at the time, because the class existed and every path resolved.

Exception types are excluded, and the distinction is the point: a collaborator is something the class reaches for; an exception is something that passes through it. The first draft flagged CoverageError, LaunchConfigError and SourceSelectionError, all of which the manager legitimately propagates.

The mutation campaign found a miss in the previous change

Reintroducing the exact GaulLookupEnricher sentence did not fail. The collaborator check only sees classes that still exist, and C-75 had deleted that one.

The real gap: the deletion never extended the deleted-symbol list — which that list's own comment demands in as many words:

A deletion PR that does not extend this regex has not finished.

Extended here; the reintroduction now fails. Four further historical mentions written yesterday were flagged by the extension and marked.

Verification

Four guards, all mutation-proven: a stale path reappearing in an ADR, the file-level escape used on a live document, a CIC with no declared subject, and the reintroduced collaborator.

356 passed / 40 xfailed / 0 failed
ruff check .  ->  All checks passed!

Register 83 / 11 open / 72 resolved.