[BUG] VSCode: Selected session highlight stays on wrong conversation after opening new chat

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

When opening a new chat in the VSCode extension, the previously selected session sometimes stays visually highlighted in the conversation list instead of the new one. This makes it unclear which conversation is actually active.

What Should Happen?

The selected/highlighted session in the sidebar should always track the currently active conversation. When a new chat is created, the highlight should immediately move to it.

Steps to Reproduce

1. Have multiple past conversations in the sidebar
2. Select and open one of them
3. Create a new chat
4. Observe: the highlight sometimes remains on the previous conversation instead of the new one

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Latest

Platform

Anthropic API (VSCode extension)

Operating System

macOS

Additional Context

Split from #34054 to keep the bug report focused.