ExitPlanMode auto-approves plans without waiting for user input

Bug Description

When using plan mode, calling ExitPlanMode immediately returns an approval result and allows the agent to proceed with execution — without actually waiting for the user to review and approve the plan.

Steps to Reproduce

1. Enter plan mode (user selects plan mode)
2. Agent explores codebase and writes a plan to the plan file
3. Agent calls ExitPlanMode
4. Expected: Agent pauses and waits for the user to review the plan file and explicitly approve or reject
5. Actual: ExitPlanMode returns immediately with "User has approved your plan. You can now start coding." and the agent proceeds to execute without any user interaction

Impact

• Agent executes code changes the user never reviewed or approved
• Defeats the purpose of plan mode entirely
• User has to manually revert unwanted changes
• Happened repeatedly in the same session despite the user calling it out

Environment

• Claude Code CLI
• Model: claude-opus-4-6
• Plan mode activated via system prompt

Additional Context

The ExitPlanMode tool result includes the text "User has approved your plan" which misleads the agent into thinking approval was granted. The user never saw the plan or had a chance to respond.