docs: fix the review findings on the hook-contract retirement

Why: a review of 4de5b6b and 3c5f6a6 found seven places that still
described the retired external hook contract as current, or that could
pass without checking anything.

Implementation Notes:
- gates.md: drop the "one caveat below" pointer; the caveat is gone.
- SIMPLIFICATION-AUDIT.md: the §7 note now says all but one entry is
  closed and lists 36 (4de5b6b) as struck. Finding 2's count chain gets
  a closing note: pre-push is 8 repo-authored hooks (10 reported).
- .pre-commit-config.yaml: the check-vale-style-sync comment points at
  case 32 (one-plugin narrowing guard), not the deleted case 33.
- ADR-0014: the retirement pointer now covers the ADR-0025 amendment
  above it too, naming case 33 and the exported hook IDs. ADR-0022 gets
  a reciprocal amended-by note on its check-release-needed comparison.
  Historical body text is unchanged.
- test-vale-wrap.sh case 32: property 3 fails when a class's corpus
  regex matches no tracked file, instead of passing vacuously after a
  layout move. The corpus regexes are now globals so a new Part D can
  point them at a missing layout and require that failure.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/adr/0022-skill-metadata-version-is-mandatory.md

@@ -110,6 +110,10 @@ Checking at commit time against `HEAD` was rejected for the inflation described
 The 17 unbumped skills took a patch bump in the commit that added the gate. A typo fix in a skill
 now costs a version bump; that is the rule working, not noise.
 
+**Amended by ADR-0014 (2026-09-16).** `check-release-needed` is retired, so the comparison below
+records the state when this ADR was written, not a hook that still runs. See
+[ADR-0014's amendment](0014-vale-prefilter-ships-from-the-plugin.md#amendment-2026-09-16-the-external-hook-contract-is-retired).
+
 The gate differs from `check-release-needed` in when it runs: that hook acts only when pre-commit
 reports a push to `main`, so a manual `pre-commit run --hook-stage pre-push` skips it, while this
 gate runs there too and checks `HEAD`. The two hooks share both known gaps. A merge made with