Inventory is one-of-one by default, so the catalog is item-keyed instead of SKU-keyed. When a piece sells, it disappears from the front counter and reappears in the "already shipped" archive.

Checkout sets parcel, crate, or oversized shipping based on the cart's pieces; Stripe webhooks fan out to Resend for the order confirmation and to a packing list the studio prints before it cures the next pour.