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>

docs/USER-GUIDE.md

@@ -386,7 +386,7 @@ GSD generates markdown files that become LLM system prompts. This means any user
 - `gsd-prompt-guard.js` — Scans Write/Edit calls to `.planning/` for injection patterns (always active, advisory-only)
 - `gsd-workflow-guard.js` — Warns on file edits outside GSD workflow context (opt-in via `hooks.workflow_guard`)
 
-**CI Scanner:** `prompt-injection-scan.test.cjs` scans all agent, workflow, and command files for embedded injection vectors.
+**CI Scanner:** `prompt-injection-scan.security.test.cjs` scans all agent, workflow, and command files for embedded injection vectors.
 
 ---