Terminal scroll position resets when Claude produces new output

Description

When Claude Code is running and producing output, scrolling up in the terminal to review previous content is impossible — the terminal immediately jumps back to the top of the command window whenever Claude writes a new line or performs an action.

This used to work fine — I could scroll up and read previous output while Claude was still working. After recent updates, the scroll position resets on every new output line.

Steps to reproduce

1. Start a Claude Code session
2. Give Claude a task that produces multiple lines of output (e.g. reading files, running tools)
3. While Claude is working, scroll up to review earlier output
4. Observe: the terminal jumps back as soon as Claude writes anything new

Expected behavior

Scroll position should be preserved when the user has scrolled up, similar to how most terminal applications handle output while scrolled.

Actual behavior

Terminal jumps to the top of the Claude Code command window on every new output, making it impossible to review previous content during execution.

Environment

• OS: macOS (Darwin 25.3.0)
• Shell: zsh