feat(ADM-018): completed feature

work/artifacts/F-022/security.json

@@ -0,0 +1,15 @@
+{
+  "feature_id": "F-022",
+  "agent": "security",
+  "verdict": "APPROVED",
+  "summary": "Security approved. No new dependencies or secrets. Checkout is authenticated, idempotency_key is required, request schema strips unknown fields, all calls go through services with parameterized SQL, and unavailable stock returns 409 before any order or reservation.",
+  "evidence": [
+    "cd project && npm audit --audit-level=high --omit=dev: found 0 vulnerabilities",
+    "Secret scan found only a test fixture password and a code comment mentioning F-023 Stripe adapter",
+    "Reviewed /checkout: authenticated and zod schema enforces idempotency_key required",
+    "Reviewed CheckoutService: idempotency lookup short-circuits; unavailable stock rejects before order/reservation",
+    "Reviewed repository SQL: parameterized queries only across all composed services",
+    "Stub payment provider has no secrets; F-023 will replace it with the Stripe adapter"
+  ],
+  "timestamp": "2026-08-15T18:27:12Z"
+}