Register due payments

This module makes it easier to chase unpaid customer and vendor items in accounting. On journal items (account.move.line) it adds a new computed field called "Remaining due days", which shows the payment due date of a line and stays empty once the line has been matched with a payment (in other words, once it is paid).

In the journal items list, a new "Overdue" filter is available next to the existing payable/receivable filters. It shows only lines whose due date is today or earlier and that are not yet matched, so you can see at a glance what is late.

From the same list or form, a "Register Payment" action opens the standard payment registration window (account.payment.register) directly, so you can record the payment for the selected line without leaving the screen. This works for individual lines, including partial invoice payments, and the payment is matched automatically.

No new menus are created; the changes appear inside the existing journal items views. The module only depends on the standard Accounting app.