Partner Credit Limit History

This module turns the credit limit on a contact into a controlled, auditable value. On the contact form, in the Sales & Purchases tab, a new "Credit Info" section shows the current credit limit as read-only, next to a "Change Limit" button.

• Clicking "Change Limit" opens a small pop-up where the user enters the new amount and a reason, then submits. The system records the previous amount, the new amount, the reason, the date and the user, and updates the contact's credit limit.
• The same section lists the full credit history of that contact, newest first, so anyone can see who changed the limit, when, from what amount to what amount and why.
• The credit limit field itself is read-only on the contact form, so it cannot be edited directly; the only way to change it is through the button and the pop-up.
• History entries are linked to the contact and are deleted automatically if the contact is deleted.
• Regular users can read the history but cannot create, edit or delete entries; only partner managers have full rights. The pop-up creates the history entry with elevated rights so that any user allowed to change the limit can do so.

The module touches the contact model (res.partner), adds a new credit history model (res.partner.credit.history) and a pop-up wizard (partner.credit.limit.wizard).