{
  "route": "/checkout",
  "cart": { "id": "cart_8f2a", "items": 3, "total": null, "currency": "USD" },
  "user": { "id": "u_4821", "plan": "pro", "region": "eu" },
  "featureFlags": { "checkout_v2": true, "express_pay": false },
  "lastAction": "CART_SUMMARY_RENDER",
  "note": "total is null → CartSummary read of total.toFixed() threw"
}