the rail's 16px hit area at z-20 sits right where the native os scrollbar
lives when the sidebar is in offcanvas mode and collapsed. this causes clicks
and drags on the scrollbar to toggle the sidebar instead on windows and linux.

scoping pointer-events-none to [data-collapsible=offcanvas][data-state=collapsed]
fixes the interception without affecting icon mode where the rail needs to stay
clickable.