[BUG] Terminal resize causes content loss - lines are disappeared when shrinking window

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 resizing the terminal window (specifically making it smaller/narrower), Claude Code's rendered content gets corrupted. Previous conversation lines are disappear upward. The display does not properly re-render or preserve the scrollback buffer during resize operations.

What Should Happen?

1. All existing conversation content should be preserved in the scrollback buffer
2. Content should reflow properly to fit the new terminal dimensions
3. The display should re-render correctly without losing any lines

Error Messages/Logs

Steps to Reproduce

1. Open terminal (I use Ghostty)
2. Launch Claude Code with claude command
3. Have a conversation (e.g., type "hello, how are you" and get a response)

<img width="727" height="587" alt="Image" src="https://github.com/user-attachments/assets/75292018-fb70-4745-aa90-cc08a58f0580" />

1. Resize the terminal window by dragging the corner to make it smaller/narrower
2. Observe that previous conversation content disappears/gets consumed

<img width="575" height="491" alt="Image" src="https://github.com/user-attachments/assets/2e8fc584-d1a8-4ed3-b123-044782daf5b7" />

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.8

Claude Code Version

2.1.9

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_