[BUG] Autocompact Buffer not clearing after /clear

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

This is related to #10857 I executed the /clear command but still I have 22% of my context occupied by autocompact buffer. Actually I'm expecting the /clear command to clear everything about the current conversation.

<img width="315" height="376" alt="Image" src="https://github.com/user-attachments/assets/cffa24ed-c041-4ee4-ba8f-c15059f9f743" />

What Should Happen?

I have a context that contains only the base context tokens not something related to compact since I discharded the whole conversation.

Error Messages/Logs

Steps to Reproduce

1. Start a conversation with opus
2. compact the conversation
3. /clear the conversation

I've still 22% context occupied by autocompact.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.15

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

I'm using claude 2.1.15 with the Visual Studio Code insider (as an extension)