Internal documentation. Added docs/plans/STORE.md. It records what Store does today, defects to fix first (paid orders store the billing address instead of the shipping address, and sellers get no new-order email), twelve decisions for the product owner, and five phases of work: discounts, tax, customers and order tools; new kinds of product; reviews and marketing; stock, shipping and returns; and in-person and wholesale selling. No product behaviour changed.
Store expansion plan
A plan in docs/plans sets out the defects to fix in Store, the decisions it needs, and the order of new Store work.