Scroll position jumps to top when new content streams in

Bug

When I'm scrolled up in the conversation (not at the bottom) and new content streams in, my scroll position jumps to the top of the list instead of staying where I was.

Expected behavior

If I've scrolled up to review earlier content, new streaming content should either:

1. Keep my scroll position exactly where it is (preferred), or
2. At most, auto-scroll to the bottom for new content

It should never jump to the top.

Actual behavior

Every time new content streams in while I'm scrolled up, the view snaps to the very top of the conversation. This makes it impossible to review earlier messages while the agent is still responding.

Reproduction

1. Start a conversation that produces a long response
2. While content is streaming, scroll up to review earlier messages
3. Observe: scroll position jumps to the top as new content arrives

Environment

• Claude Code CLI (terminal TUI)
• macOS