Create products in batch

Create or update multiple ecommerce products in a single request. The `products` array accepts up to 100 product objects for creation (or up to 1000 when `updateEnabled` is `true` and the account has an increased limit). Each product requires a unique `id` and `name` (name is mandatory for creation only). When `updateEnabled` is `false`, all products are inserted as new; if any ID already exists, a `400` error is returned. When `updateEnabled` is `true`, existing products are updated and new ones are created via upsert. Duplicate IDs within the same request payload are rejected. The response returns the count of created and updated products.