Plan mode ExitPlanMode button misleadingly shows 'ready to code' prompt

Problem

When an agent calls ExitPlanMode to exit plan mode (even just to run a simple git command), the UI presents a prompt to the user that appears to indicate the agent is about to start coding/implementing. This causes users to reject the action when the agent's actual intent is just to leave the read-only plan mode state.

Steps to reproduce

1. Enter plan mode (e.g., to write a plan document)
2. Write the plan to a file
3. User asks to push the plan to a branch/PR (requires git commands)
4. Agent calls ExitPlanMode — user sees a prompt that looks like "ready to implement"
5. User rejects because they don't want implementation, just a git push
6. Agent is stuck in read-only plan mode unable to run any commands

Expected behavior

The ExitPlanMode UI should make it clear that this is simply exiting the read-only state, not committing to implement the plan. Perhaps:

• "Exit plan mode" (neutral) instead of language suggesting coding is about to begin
• Or allow the agent to provide context text that's shown to the user (e.g., "Exiting to run git commands — no implementation")

Impact

In the observed case, the user had to reject ExitPlanMode 3 times before understanding (via back-and-forth) that it was just a state transition, not an implementation trigger. This created unnecessary friction.