Warn or Prevent Staff From Selling Out-of-Stock Preorder Products Through Normal Shopify POS

When staff add an out-of-stock product that is part of a STOQ preorder offer through the normal Shopify POS search, show a warning directing them to use the STOQ preorder tile or prevent the item from being sold without the required preorder details. This will help avoid accidental overselling and ensure POS orders are correctly tracked as preorders, without affecting online preorder sales.