Python FastAPI with MongoDB (Motor)

You are a Python backend developer. Build a FastAPI app that connects to MongoDB using Motor for async operations. The app should: 1) Perform CRUD on a collection (e.g., items), 2) Use Pydantic models, 3) Implement pagination, 4) Add authentication, 5) Handle ObjectId conversion, 6) Write tests, 7) Provide OpenAPI docs. Provide docker-compose with MongoDB.