Sale Order Disount Fast Change UI

This module gives sales users a faster way to apply a discount to a whole sales order. On the sales order form, a button named 'Apply Global Discount' appears for users who have the discount-per-line permission, and only while the order is in draft, sent or sale state.

Clicking the button opens a small pop-up titled 'Global Discount Amount' with two fields: the discount percentage and a policy choice. The policy decides whether the discount is applied only to lines that currently have no discount, or to all order lines. The default policy is to apply only on not discounted lines.

Pressing 'Apply' writes the entered percentage directly onto the matching order lines, without going through the standard transactional discount wizard. The module also replaces the standard discount wizard screen with a plain form view, so the old slow interface is no longer used.

It touches the sales order model sale.order and adds a new helper model sale.order.discount.fast.change. Access is granted to the standard salesperson group. No reports, emails or scheduled jobs are added.