Add keyboard shortcuts for quickly switching reasoning effort and model

Feature request

It would be helpful to have keyboard shortcuts or a command-palette action for quickly switching the model reasoning effort, and possibly the model itself.

Motivation

When starting a new Codex session, I often choose a different reasoning level depending on the difficulty of the task. Right now this requires using the mouse to open the model/reasoning selector and change the setting manually. Doing that repeatedly across new sessions adds friction and interrupts the workflow.

Suggested behavior

Possible approaches:

• Add shortcuts to cycle reasoning effort, for example low / medium / high.
• Add shortcuts or command-palette actions for selecting a specific reasoning effort.
• Optionally support quick model switching in the same way.
• Show a lightweight confirmation/toast after switching so the active setting is clear.

This would make it easier to adapt Codex to quick/simple tasks versus deeper implementation work without leaving the keyboard.