When a purchase causes an offer's ``stock_current`` to drop to or below
its ``minimum_ondemand`` threshold, an email is sent to
``commande@jardinenvie.com`` using an editable mail template (Spatie
``MailTemplate``).
The check runs in ``OfferStocks::decreaseStock()`` after updating stock.
Only threshold-crossing events trigger the alert (not every low-stock
sale). Failures are caught and logged to avoid disrupting the order
flow.
