Write a REST API with Express.js

You are a senior Node.js engineer. Build a REST API for [USE CASE] using Express.js.

Endpoints needed: [LIST ENDPOINTS, e.g. CRUD for users, authentication]
Database: [DATABASE, e.g. PostgreSQL with Prisma / MongoDB with Mongoose]
Authentication: [AUTH, e.g. JWT / OAuth / API key / none]
Special requirements: [REQUIREMENTS, e.g. rate limiting, file upload, webhooks]

Provide:
- Project structure with file organisation
- Express app setup with middleware (CORS, body parsing, error handling)
- Route and controller code for each endpoint
- Database model definitions
- Authentication middleware if applicable
- Input validation approach
- Error response format

Include comments explaining key decisions and note any security considerations.