CartItem

One line of an open cart. FLAT, one row per (producto, opcion) — the same parser that reads an order's items reads these. A cart has NO frozen snapshot (schema invariant), so name / sku read from the LIVE producto and opcion, and every row carries its own `price`.

{
  "product_id": "9201",
  "name": "Remera Premium",
  "option_id": "555",
  "option_name": "Azul / M",
  "sku": "REM-001-AZ-M",
  "quantity": 3,
  "price": 4500.0
}