[BUG] VS Code extension: tooltips for truncated session names are also truncated

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?

When a session name doesn't fit in a tab, it gets truncated and suffixed with an ellipsis. This is fine, but the typical UX for these situations is to surface the entire name on mouse over. This doesn't happen:

<img width="584" height="137" alt="Image" src="https://github.com/user-attachments/assets/2c08b47e-4959-4b56-81a1-4991512e116b" />

What Should Happen?

The tooltip should show the complete session name.

Steps to Reproduce

1. Create or find a session whose name exceeds the tab width (tabs should ideally auto-expand when there's sufficient horizontal space - separate issue)
2. Mouse over

Is this a regression?

No, this never worked

Claude Code Version

2.1.186

Platform

Other

Operating System

Ubuntu/Debian Linux