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>

scripts/lint-test-file-count.allowlist.json

@@ -26,7 +26,7 @@
     "graphify": {
       "files": [
         "bug-622-graphify-optional-graph-html.test.cjs",
-        "graphify-auto-update.test.cjs",
+        "graphify-auto-update.slow.test.cjs",
         "graphify-query.test.cjs",
         "graphify-visualization.test.cjs",
         "graphify.test.cjs"
@@ -82,8 +82,8 @@
     },
     "security": {
       "files": [
-        "security-prompt-injection.test.cjs",
-        "security-scan.test.cjs",
+        "security-prompt-injection.security.test.cjs",
+        "security-scan.security.test.cjs",
         "security.test.cjs"
       ],
       "issue": "TBD"