Plan mode 'accept plan' prompt is ambiguous - unclear if it saves file or starts execution

Description

When using plan mode to create/update a plan document (not implement code), the ExitPlanMode approval prompt is confusing.

Scenario

1. User asks Claude to update a design plan document (e.g., create V2 of a planning doc) and save it to a specific file path
2. Claude writes the plan to the temporary plan file in .claude/plans/
3. Claude calls ExitPlanMode
4. User sees "accept plan" prompt

Problem

The user expected "accept" to save the plan to the requested file path. Instead, it's unclear whether "accept" means:

• Save the plan file to the user's requested location
• Start executing the implementation steps in the plan

The user wanted the plan saved to a project documentation folder, not to start implementing code changes.

Expected behavior

The prompt should distinguish between:

• "Save plan to file" (for planning/documentation tasks)
• "Execute plan" (for implementation tasks)

Or allow Claude to specify the intent when calling ExitPlanMode.