The recessed task-list box had flex:1, so its background filled the full
height and ran well past the last task. Move the scroll onto .tasks-terminal
and let .tasks-list size to its content, so the box ends at the last task
(and still scrolls when the list overflows). Scrollbar styling follows to
the new scroll container.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: librelad <librelad@digitalangels.vip>