chore(gates): retire the external pre-commit hook contract

Why: .pre-commit-hooks.yaml and its release-tag gate served external
consumers that do not exist. No repo on the Gitea instance pins these
hooks, and the README names apm as the only supported install path. The
mechanism was also already failing: skill-size-check.sh changed after
v2.0.1 with no tag cut, and the gate cannot fire through Gitea's merge
button. (Simplification audit finding 36.)

Implementation Notes:
- Delete .pre-commit-hooks.yaml, scripts/check-release-needed.sh,
  tests/test-check-release-needed.sh and tests/test-vale-hooks-consumer.sh,
  and remove the check-release-needed pre-push hook. The repo: local
  skill-size-check and vale-audit-prefilter-* hooks are unchanged.
- ADR-0014 is amended, not retired: its runtime decision to bundle Vale
  inside factory-audit stands. The amendment keeps the entry[0]-only
  constraint (LESSONS.md:101,105) in case the export returns. ADR-0025
  gets a pointer.
- test-vale-wrap.sh: drop case 33 (the cross-manifest drift check) and
  case 28's hook-scope half, which read the published manifest. Case 32
  now also requires each hook to select every tracked file of its class,
  which keeps case 33's one-plugin-narrowing guard, with a mutation test.
- test-skill-size-check.sh and test-adr0020-contract.sh now assert the
  hook contract and verbose: true on .pre-commit-config.yaml only.
- gates.md: pre-push count goes from 9 to 8 authored hooks (11 to 10
  reported), and the Release table, the External consumers section and
  the two-manifest scope table are removed. README and script/test
  comments no longer describe the export as live. The resolver comment
  is edited identically in both copies.
- The v1.0.0/v2.0.0/v2.0.1 tags are left in place; they are inert.

ADR: 0014
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/check-skill-version-bump.sh

@@ -79,9 +79,9 @@ set -euo pipefail
 #     all, so this script checks HEAD — the pushed ref only if checked out. The
 #     script cannot recover either case: the ref list is gone by the time it
 #     runs. Push refs one at a time to be sure each is checked.
-#   - A PR merged via Gitea's merge button runs no local hook at all (the same
-#     gap check-release-needed has). Closing it requires a server-side CI job,
-#     which this repo does not have yet.
+#   - A PR merged via Gitea's merge button runs no local hook at all.
+#     Closing it requires a server-side CI job, which this repo does not have
+#     yet.
 
 # Byte-wise regex matching and messages: path bytes are matched against
 # SKILL_PATH_RE below and must not depend on the caller's locale.