Replaces the full-variant flex layout with a single CSS grid owning the
messages column, input bar, and context sidebar. Messages and input bar
share a centered ~820px reading track (--chat-reading-width token) so
the mic button can't get pushed off-screen on wide monitors, and the
context sidebar spans grid-row 1/-1 so it runs the full height from the
chat header down to the bottom edge instead of stopping above the input
bar.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
bvandeusen
ad4fe3d783