Contribute a code change

This file has moved. Its content now lives in two documents:

• CONTRIBUTING.md — the contribution journey: Propose a change or claim an issue, Submit a pull request, What happens during review, and the Contributor License Agreement (CLA).
• DEVELOPMENT.md — environment setup and test mechanics: Prerequisites, Fork and clone the repository, Set up your development environment, Configure backends for testing, Test code changes, and Test performance.

If you're not sure which one you need: looking to open a pull request or understand the review process, start with CONTRIBUTING.md; looking to get a local dev environment running, install dependencies, configure a database backend, or run tests, start with DEVELOPMENT.md.