Pricing and promotions

Prices

setRetailPrice publishes a PriceBookEntry for a price book and variant: amountCents, minQuantity, startsAt, endsAt. The store's default price book wins; the variant default price is the fallback.

Tax

configureStoreTaxRate sets a store tax rate in basis points per TaxCategory (onboarding creates Standard and Exempt).

Promotions

configurePromotion creates a Promotion with rules. /dashboard/platform/promotions lists them by status, window, and use. Percentage promotions need basis points: "Percentage promotions require basis points". Cashiers apply them with applyPromotionToCart; each use writes a PromotionRedemption.