Create New Thread & Implement Plan

What variant of Codex are you using?

MacOS App / CLI

What feature would you like to see?

In the app and CLI, would be nice if when done the planning phase it had an option to start a new thread and implement the plan so you start with just a spec file and fresh context, in both app and cli, just like how Claude Code does it.

Also should be an option to change the thinking level when starting plan, maybe like a three step:

1) Implement Plan
2) Cancel

1 > 1) Continue in thread
2) Implement plan in new thread

1/2 > Thinking level for implementation: XH/H/M/L

Additional information

_No response_