Stop animating the app shell height when the keyboard opens: per-frame
reflow plus the scroll-follow chase caused visible micro-jitter on the
composer and pinned chat. The shell layout now snaps exactly once per
open/close at an invisible choreography point, while the composer and
pinned chat content slide via compositor-only transforms in sync with
the keyboard. Dismissal starts from the textarea focusout (no bridge
latency), runs a shorter 0.2s leg, and the WebKit form accessory bar
is disabled. Composer keeps a 12px gap above the open keyboard.
Bohdan Triapitsyn
531039b690