Scroll position repeatedly dragged back to bottom while a turn is streaming output

[Raymond8196]

Problem

While the current turn is streaming output, scrolling up to read earlier content gets repeatedly dragged back to the bottom. The viewport does not stay where the user scrolled, making it nearly impossible to read previous content during output.

Steps to reproduce

1. Send a request that produces a long, continuously streaming response.
2. While output is still streaming, scroll up away from the bottom.
3. The viewport is pulled back to the bottom; scroll up again and it gets pulled back again, in a loop.

Expected behavior

Once the user actively scrolls up, auto-follow should stop immediately and not resume until the user returns to the bottom (or clicks the scroll-to-bottom control). During streaming, the reading position should be stable.

Observed patterns

• The pull-back repeats continuously while output streams.
• Even after stopping an upward scroll, the viewport sometimes gets dragged once more "a beat later".

[lifelmy]

I would like to work on this. I will first trace the streaming scroll ownership and add a regression test proving that explicit user scroll suspends auto-follow until the viewport returns to the bottom. I will keep the change scoped to this issue, run the repository-required frontend checks, and open only a linked draft PR once the behavior is verified.