Add /resume command inside interactive Codex sessions

What feature would you like to see?

It would be really helpful to have a /resume command available directly inside the interactive Codex CLI, similar to how $ codex resume works from the shell.

Right now, running codex resume from the terminal works perfectly, but once you’re already inside a Codex session, there’s no equivalent slash command to trigger the same behavior. Having /resume available in-session would make the workflow much smoother and more intuitive, especially when switching contexts or continuing previous work without leaving the interactive mode.

This would align nicely with other built-in slash commands and make the overall experience more consistent.

Additional information

_No response_