Can I vibe code Commerce Layer?

Build a multi-market headless commerce API service using Node.js, Fastify, and PostgreSQL with Prisma ORM.

1. DATA MODEL:
- Markets: id, code (e.g. US, EU), currency_code, tax_inclusive (boolean).
- SKUs: id, code, name.
- Price Lists: id, market_id, currency_code.
- Prices: id, price_list_id, sku_id, amount_cents.
- Stock Locations: id, name, priority.
- Stock Items: id, stock_location_id, sku_id, quantity, reserved_quantity.
- Carts: id, market_id, currency_code, status (draft, pending, completed), total_amount_cents.
- Line Items: id, cart_id, sku_id, quantity, unit_amount_cents.
- Orders: id, cart_id, market_id, payment_status, fulfillment_status.

2. API ENDPOINTS:
- POST /api/carts: Initialize cart assigned to a specific market code.
- POST /api/carts/:id/line_items: Add line item. Automatically lookup valid price for cart's market_id. Verify available stock (quantity - reserved_quantity > requested_qty).
- POST /api/carts/:id/checkout: Lock stock with atomic transaction (increment reserved_quantity). Create Stripe PaymentIntent with exact cart total and currency.
- POST /api/webhooks/stripe: Handle payment_intent.succeeded. Transition order to 'paid', decrement stock quantity, clear reserved_quantity, mark cart 'completed'. Idempotent using Stripe event ID log table.

3. FAILURE HANDLING & CONCURRENCY:
- Implement PostgreSQL row-level locking (SELECT FOR UPDATE) on Stock Items during cart checkout to prevent overselling.
- Cart pricing must be immutable once checkout step is initiated.
- Payment webhook failures must retry automatically using standard HTTP status responses.

4. OUT OF SCOPE:
- Do not build a frontend UI; strictly output clean OpenAPI REST endpoints.

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