test(suites): seed security/slow/integration suites via measured retags

Renames (git mv) with all references updated (ci-test-scope RULES,
windows-parity allowlist, test-file-count allowlist, docs in 6 locales):

- 5 scanner tests -> *.security.test.cjs — the 'Run security tests' CI step
  ran zero files since the suite taxonomy landed; it is now honest.
- graphify-auto-update -> *.slow.test.cjs (36s, slowest file in the suite;
  e2e gsd-tools spawns) — runs on full-matrix lanes and push to next.
- installer-migration-install-integration -> *.integration.test.cjs
  (13s; an integration test by its own name).

Coverage gate measured after retags: 88.55% lines (gate 70%).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/fixtures/adversarial/security/README.md

@@ -1,7 +1,7 @@
 # Adversarial security fixtures (#3596)
 
 Reusable hostile payloads consumed by
-`tests/security-prompt-injection.test.cjs`.
+`tests/security-prompt-injection.security.test.cjs`.
 
 The fixtures here are pure data — they are loaded by the test as input
 to the production code under test (hooks, validators, sanitizers, CLI).