An app-controlled animated cart LINE ITEM (not a full cart) — arrival, quantity/total morph, variant crossfade, price-change, limited/unavailable, removal→Undo→restore, with optimistic mutation + automatic rollback and honest failed/Retry. Never touches a backend or payment; price/inventory are app-owned. No manipulative urgency.
pnpm dlx shadcn@latest add "https://motiq.dev/r/cart-item-transition.json"