The collapsed rail becomes a 56px icon column (24px controls between 16px
paddings) carrying expand, new session, search, and new workspace — each
aligned with its expanded counterpart; rail search expands the sidebar and
focuses the search box. Collapse/expand now animates: the frame transitions
grid-template-columns (and the surviving handle its left) on the deepsuite
sider curve — --ds-ease-in-out over --ds-transition-duration-slow, supplied
by ui-theme's base sheet. Transitions pause during drags (data-dragging on
the frame, set for the whole gesture) and under prefers-reduced-motion.
imccyu
5da8e3b787