Sale coupon free shipping default product

This module adds a single setting that saves you from creating a separate product each time you make a free shipping promotion.

Where it appears: - In Sales settings, right after the coupon/promotion section, there is a new field "Default promo product for free shipping". - The field only accepts products of type service.

What it does automatically: - When a promotion program is created with the reward type "free shipping", Odoo looks at the default free shipping product configured on the company and uses it as the reward product for that promotion. - If no default product is configured, nothing changes and the promotion is created as usual.

What it touches: - The company record stores the chosen default product (res.company). - The setting is exposed through res.config.settings. - The promotion program model coupon.program is extended so the default is applied at creation time.

Business benefit: consistent accounting and reporting for free shipping rewards, because all free shipping promotions point to the same service product instead of many one-off products.