feat(F-057): completed feature

work/artifacts/F-057/security.json

@@ -0,0 +1,13 @@
+{
+  "feature_id": "F-057",
+  "agent": "security",
+  "verdict": "APPROVED",
+  "summary": "No security boundary touched. Items already validated server-side: route handler enforces isUuid on productId/variantId and integer 1..99 on quantity. Client-side mapping trusts no untrusted field — productId/variantId/quantity come from CartContext which is populated from the store catalog. No new auth surface.",
+  "evidence": [
+    "Items forwarded are productId, variantId and quantity — same fields the route already validates via isUuid and parseQuantity",
+    "No new HTTP endpoints, no new cookies, no new headers, no new env vars",
+    "No user-controlled strings are rendered server-side (only IDs)",
+    "git diff shows zero changes outside project/frontend/src/components/checkout/CheckoutClient.tsx"
+  ],
+  "timestamp": "2026-08-19T13:35:00Z"
+}