Delete product

## Delete product Deletes a product owned by the authenticated store, first removing all of its app and modifier join rows. ### Authentication Requires a Merchant API key in `x-api-key` with scope `Merchant.product.delete`. ### Path params - `id` (required) — the product UUID. ### Behavior & side-effects - Validates the product exists in your store (400 `Product with id <id> not found` otherwise). - In a transaction, deletes related `productApps` and `productModifiers` rows, then deletes the product. Returns a confirmation message. --- **Notas:** Join rows are deleted in a transaction; the product delete itself runs after that transaction. Product must belong to the caller's store.