Coupon Promotion Discount in Field Order Line Link

This is a technical bridge module with no new screens or menus. It connects two other modules: one that links coupon promotions to sales order lines, and one that keeps the promotion discount in a dedicated field on the order line.

When Odoo applies a reward discount to sales order lines, the module extends the existing behaviour on sale.order. After the standard logic determines which lines receive the reward discount, it writes the promotion program onto those lines by setting coupon_program_id. This means each discounted line keeps a reference to the promotion program that generated it.

• No new menus, buttons, reports or settings are added.
• No new models are defined; it only inherits sale.order.
• The automatic behaviour is limited to tagging the affected order lines with the promotion program when a reward discount is applied.

Because the module contains only this small inheritance and no data files, its visible effect depends entirely on the two modules it depends on. It does not add checks, emails, scheduled jobs or default values on its own.