Order Processing System

Problem/Feature Description

A food delivery startup needs an order processing backend built with Node.js, TypeScript, and Express. The service uses PostgreSQL via the pg package. The database is accessible via a DATABASE_URL environment variable.

The system needs to support:

• Creating a new order: accepts a customer name, delivery address, and a list of order items (each with menu_item_id, quantity, and price_cents). The order and all its items must be saved together atomically -- if any item fails, the entire order must be rolled back.
• Cancelling an order: sets the order status to "cancelled" and refunds inventory. This also needs to happen atomically.
• Getting an order by ID, including its items
• Listing orders by status (received, preparing, ready, delivered, cancelled)

The orders table has: id (serial), customer_name, delivery_address, status (default 'received'), total_cents, created_at, updated_at. The order_items table has: id (serial), order_id (FK), menu_item_id, quantity, price_cents.

Output Specification

Produce:

• db.ts -- Database connection module
• orders.ts -- Functions for all four operations listed above
• package.json -- With required dependencies
• migrations/001_create_orders.sql -- SQL migration for both tables

The code should be complete TypeScript with no placeholders or TODO comments.