feat(F-090): completed feature

work/artifacts/F-090/reviewer.json

@@ -0,0 +1,13 @@
+{
+  "feature_id": "F-090",
+  "agent": "reviewer",
+  "verdict": "APPROVED",
+  "summary": "The catalog response now exposes existing brand and expiration data, and SKU/EAN cells render the row state that is updated by the existing variant PATCH flow.",
+  "evidence": [
+    "serializeProduct includes brand and expirationDate without changing persistence or routes",
+    "SKU and EAN non-editing cells use r.variant values updated after save",
+    "Existing PATCH /products/:id/variants/:variantId remains the persistence path",
+    "Root and admin TypeScript checks pass"
+  ],
+  "timestamp": "2026-08-20T19:40:00Z"
+}