You set it up for them automatically for them. Just like you set up a new environment automatically from scratch each time you run tests or when running the AI. See eg https://code.visualstudio.com/docs/devcontainers/containers or https://github.com/features/codespaces for some established standards for doing this, but you could also roll your own custom system.

GitHub's codespaces also drive home how the customer/user only needs a browser, which even people in legal will have. No additional software required on their end.