The sales margin feature has been modernized and reorganized to align with Odoo's newer framework standards. This improves maintainability and keeps margin reporting and tests reliable without changing the core business workflow.

Task: https://www.odoo.com/web#id=13378&view_type=form&model=project.task&menu_id=3942&action=327
Pad: https://pad.odoo.com/p/r.bSJGE9rAhvMGNKC7

The stock barcode app now matches the stock dashboard by hiding internal transfer options when multi-location management is not enabled. This reduces confusion for warehouse users and adds automated checks to help keep the behavior reliable.

- Add tests
- Small fixes