Roll back the Chat collapse, Zen mode, composer reflow repair, and related regression fixture after they interfered with the native prompt. Keep only the collapsed-sidebar agent-tree hiding selector.
After removing the former collapse feature, force a one-time reflow of DSH input mirrors and textareas and refresh the conversation composer-height variable. Restore every temporary inline style immediately and mark each mounted input so normal prompt behavior remains entirely native afterward.
Remove the persistent Chat collapse feature, its button, storage state, seat attribute, and sizing selectors because they interfere with DSH composer auto-height measurements. Clear stale collapse state on startup and keep only the Zen control, which temporarily removes the composer from flow without constraining its measured height.
Derive conversation roots from composer seats instead of every nested phase element, remove invalid and duplicate control groups, and anchor the sole surviving group directly before Git Working Dirs. Preserve Zen relocation and measurement-safe composer collapse.
Insert Chat and Zen immediately before the Git utility group in normal mode, then relocate them to the conversation root while Zen hides the header. Collapse the composer with measurement-safe clipping instead of display none to prevent incorrect empty textarea height after restoring it.
Mount Chat and Zen controls on the conversation root at top-right so they cannot overlap the scroll-to-bottom affordance. Hide the semantic conversation header in Zen mode and keep the exit control independent from composer visibility.
Keep hidden sidebar and details columns participating in CSS Grid so the center conversation remains in the middle track. Hide their contents with visibility and disable interactions while removing only resize handles from layout.
Hide workspace and agent content when the native sidebar rail is collapsed. Add persistent whole-composer collapse controls and a temporary Zen mode that removes side panels, chat header, and composer while keeping an in-chat exit control available. Cover state transitions, Escape handling, React rerender idempotence, and cleanup with a dependency-free DOM regression test.
