account_invoice_warn_message

Purpose

Surface partner invoice warning messages on customer invoices to alert users during drafting.

Features

account.move: Computes a warning message on draft customer invoices and refunds by combining the partner and its parent's invoice warning texts when flagged as warnings.
account.move: Clears the invoice warning message when no warning applies, the invoice targets vendors, or the document is posted to prevent stale alerts.
account.move form: Displays the computed warning text as a warning banner in the invoice header for immediate visibility while editing.