Add devcontainer and GitHub Codespace support

[christopherco]

It would be great to have a devcontainer that could be launched via GitHub Codespaces and add a Codespaces link to the Contributing.md

[copilot-swe-agent]

@christopherco Unfortunately I hit an unexpected error while trying to work on issue #284. I've automatically reported this to GitHub.

You can ask me to try again later by unassigning and then reassigning the issue to me again.

If you want to contact GitHub about this error, please mention the following identifier so they can better serve you: 31512f60-9dbe-402c-8526-05df88a6e733

Sorry for the inconvenience!