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>

.pre-commit-config.yaml

@@ -183,15 +183,6 @@ repos:
         pass_filenames: false
         always_run: true
 
-      - id: check-release-needed
-        name: Check a release tag covers .pre-commit-hooks.yaml's paths
-        description: On push to main only, fail if files exposed via .pre-commit-hooks.yaml changed since the last tag
-        entry: bash scripts/check-release-needed.sh
-        language: system
-        stages: [pre-push]
-        pass_filenames: false
-        always_run: true
-
       - id: check-skill-version-bump
         name: Check changed skills bump metadata.version
         description: On every push, fail if a skill directory changed (tests/ excluded) since the merge-base with main without its SKILL.md metadata.version rising (ADR-0022)
@@ -203,7 +194,7 @@ repos:
         # Baseline is the merge-base with origin/main (falling back to main),
         # not the remote branch tip: readers install from main. Fails closed
         # when no main ref resolves. Merges through Gitea's merge button run no
-        # local hook, so they bypass this, just as they bypass check-release-needed.
+        # local hook, so they bypass this.
 
       - id: validate-marketplace
         name: Validate marketplace manifest