Allow changing reasoning/thinking effort on the fly in the CLI with a slash command

What variant of Codex are you using?

CLI codex-cli 0.128.0

What feature would you like to see?

To switch the model effort/reasoning, I need to quit the CLI and then resume it by passing a config flag with -c. It would be far more ergonomic to allow changing the reasoning on the fly with a slash command such as slash effort or /reasoning or /thinking.

Alternatively, you could also allow users to toggle or tweak the effort when they select the model with /model.

Additional information

_No response_