Custom product number on product

Product number should suggest number in the same way as in Offer with "4 digit number"

Conflict check - when entering a number, a duplicate check must be performed. This can be done in 2 ways...wait for 2 seconds or leave the field by clicking on the outside or in a new field. In the event of a conflict, the field must have a red border and a help text stating what has happened and a recommendation. We must also check whether the number has already been used in accounting.

Starting point: Project number, Product number - the backend must be able to send a call to external accounting to check if the number exists to avoid conflicts already when filling in the number.