Figure out and document how to use devcontainer with GitHub codespace

I discovered that GitHub codespace also supports devcontainer.

https://github.com/nodejs/node/pull/60472#issuecomment-3467843933

This means for new Node.js contributors, they do not even need to download or install anything locally to start hacking on Node.js. Just click a few buttons on GitHub and they can start working on changes in the browser, and they can run tests in the container from the code space etc. as well. This might be very useful in code and learn sessions.

I don't know what extension codespace supports, but at least debugging the JS part of Node.js should be possible if the ports are set up correctly. One can always do command line debugging in the terminal in the code space as well. Or good old printing.

Codespace seems to be a paid feature but there's free tier available (?) so we'd be careful about directing people to it though

まず現在のdevcontainer設定と、GitHub Codespacesに関するリンク先のNode.js pull-requestの議論を確認します。プロジェクトをCodespaceで開き、テストを実行し、デバッグする手順を文書化し、利用可能な拡張機能と有料または無料ティアにおける制限を明確に記載します。