feat(inventory): check stock to create reservation (#7209)

packages/core/types/src/inventory/mutations/reservation-item.ts

@@ -45,6 +45,10 @@ export interface CreateReservationItemInput {
    * The reserved quantity.
    */
   quantity: number
+  /**
+   * Allow backorder of the item. If true, it won't check inventory levels before reserving it.
+   */
+  allow_backorder?: boolean
   /**
    * The description of the reservation.
    */