Order API for a Customer Portal

Problem Description

An online retailer needs a backend API for their customer portal where customers can place and track orders. Each order belongs to a customer and contains one or more line items. Customers should be able to see their own orders and admins should be able to see all orders.

Build a Node.js/Express REST API that supports:

• Listing all orders (admin) with filtering by status (pending, shipped, delivered, cancelled)
• Listing orders for a specific customer
• Getting the details of a single order including its line items
• Creating a new order with multiple line items in a single request
• Updating an order's shipping address (without affecting other order fields)
• Cancelling an order (only if it has not shipped yet)
• A batch endpoint to update the status of multiple orders at once (e.g., marking 20 orders as "shipped")

Orders have: id, customer_id, status, shipping_address, total, created_at. Line items have: id, order_id, product_name, quantity, unit_price.

Output Specification

Implement the API in a src/ directory with an entry point at src/app.js (or src/app.ts). Use SQLite or in-memory storage.

Produce a package.json with all dependencies.

Do not start the server — just produce the source files.