The composer seat is one node laid out against two different edges: in Chat it
is a sticky child of the column's scroller and rides its content box, which a
space-consuming scrollbar shortens, while a view declaring a composer overlay
gets an absolutely positioned seat against the padding box, which no bar
reduces. With the transcript scrolling the two tabs disagreed by the bar's
width, so the centred input card moved 4px sideways on every switch — and the
same 4px inside Chat when a growing transcript began to scroll.
The column now reserves its scrollbar gutter unconditionally and states the
overlay branch a scroll container on the same axes, so both states measure
against the same width.
Making `.sources` a scroll container turned its `padding-left` from spacing
into a correctness constraint. A scroll container clips inline-start overflow
with no way to scroll it back, and `::marker` is right-aligned to the content
edge, so past nine sources the markers rendered as `0.` and `1.` where `10.`
and `11.` belonged.
`searchMaxResults` is an unbounded positive integer, so size the padding in
`em` against the list's own font to hold a three-digit marker. The browser e2e
measures a `999. ` marker in that inherited font and requires the computed
padding to be at least that wide, pinning the room against the widest marker
rather than one fixture's source count.
PR #1003 re-recorded this golden from a base that predated PR #1150, which
disables the branch control on any message that is not a completed turn's
tail. Both landed on master, whose CI skips the snapshot lane, so the
conflict only surfaces on PRs. The first message's control is now disabled
with its explanatory text.
jsdom resolves no CSS Modules layout and reports scrollHeight === clientHeight
for every element, so the unit test cannot witness the scroll the .sources
max-height produces. Drive it in the real browser instead.
The web-search-round search double now returns 12 provider results with a
title, snippet, and date each. That pins the seam's cap end to end for the
first time in a real composition — searchMaxResults keeps 8, the model-visible
text carries the kept titles and none of the dropped URLs, meta.truncated is
true — and 8 such rows overflow the 320px container. A case after the aria
golden expands the row and asserts 8 <li>, no button, the truncation
indicator, and computed max-height/overflow-y with scrollHeight > clientHeight.
The recorded stream and the aria golden are unchanged: replay is a positional
cursor over the fixture's chunks and the search double is a separate local
endpoint, while the card is collapsed at capture time.
