The instant scroll runs on every step of a turn, so it now follows new
content only while the view is at the end of the thread (within 80px).
Scrolling up to read something stays put until the person comes back
down or sends the next message, which returns them to the end.
Co-Authored-By: Claude Fable 5 <[email protected]>
scrollIntoView({ behavior: 'smooth' }) on the thread's nested scroller never
moved it in Chrome — measured live: scrollTop stayed 0 after sending and
after the reply, while the instant form scrolled to the end. A long
conversation therefore showed its oldest messages after every turn, with
the new reply out of view below. Instant it is.
Co-Authored-By: Claude Fable 5 <[email protected]>