Prevent Codex CLI from reading certain files via the sandbox (source code)

= Prevent Codex CLI from reading certain files via the sandbox

* https://stackoverflow.com/questions/79959031/how-to-prevent-codex-cli-from-reading-certain-files-or-directories-via-sandbox
* https://www.reddit.com/r/codex/comments/1s0vaea/disallow_codex_read_env/
* https://www.reddit.com/r/ChatGPTCoding/comments/1mkx3yy/restricting_access_to_sensitive_files_env_etc_in/