[FEATURE] Allow model switch from plan approval menu

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When using plan mode, a common workflow is to use a more capable model (e.g., Opus) for planning and a faster/cheaper model (e.g., Sonnet) for implementation. However, once the plan approval menu
appears ("Would you like to proceed?"), the terminal input is captured by the numbered options and it is no longer possible to run slash commands like /model sonnet.

Current workaround

1. Accept the plan (option 1 or 2)
2. Press ESC to interrupt execution
3. Run /model sonnet
4. Send a "continue" message to resume

This is functional but requires an extra interruption and a "continue" prompt that feels unnecessary.

Proposed Solution

• Allow a 4th option in the plan approval menu to switch the model before proceeding, or
• Keep the slash command input accessible while the plan approval menu is shown, so the user can run /model <model> before selecting an option.

Why this matters

The plan mode is designed to separate thinking from doing. Pairing it with model switching (expensive model to plan, cheaper model to execute) is a natural and cost-effective workflow, but the
current UX makes it unnecessarily cumbersome.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_