Display promo code on product pages and block stacking with product discounts

Merchant wants the ability to display a promo code directly on product pages and ensure that the promo code must be entered in order to receive the sale (prevent customers from stacking automatic product discounts with the promo). Request a feature to: 1) expose/render a discount code on storefront product pages (banner/widget) and 2) add discount-stacking controls or exclusion rules so that code-based discounts cannot be combined with automatic product discounts.