vmall/openspec/changes/archive/2026-09-17-cart-checkout-orders/tasks.md

Tasks: cart-checkout-orders

1. Schema

• Migration: orders, order_items; order status enum; order_no sequence

2. Cart (Redis)

• GET /api/cart, POST /api/cart/items, PUT/DELETE /api/cart/items/{sku_id}
• Cart read joins SKU/product snapshots; rejects inactive/unpublished SKUs

3. Checkout & orders

• POST /api/orders/checkout (one order per shop, tx: stock decrement + order insert, cart clear)
• GET /api/orders (mine, paged), GET /api/orders/{id}
• POST /api/orders/{id}/pay (mock) and /cancel with state rules
• GET /api/shop/orders for merchants; platform admin list

4. Tests

• cargo test: multi-shop checkout splits orders, insufficient stock → 409, cancel rules, stock restored on cancel