[BUG] 2.1.78 breaks previously working notifications in iterm2 + tmux

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?

In 2.1.78+, notifications don't work in my setup (iterm2 + tmux). They do work in 2.1.77 and below.

Instead, i see notification text appear the bottom of the terminal (which corrupts the termianl output)

What Should Happen?

Notifications should appear

Error Messages/Logs

<img width="336" height="33" alt="Image" src="https://github.com/user-attachments/assets/f7097489-14f1-4b0e-aff2-737e194cc9cd" />

Steps to Reproduce

1. Use iterm2 with all notification settings enabled correctly
2. tmux -CC
3. tmux set -g allow-passthrough all (if on newer tmux)
4. launch claude
5. wait for claude to notify you

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.77

Claude Code Version

2.1.81

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_