Search: DS renders dumb input, app owns filterQuery state and
passes it to each SidebarTree. Icon-rail click: fires both
onCollapseToggle and onToggle simultaneously, no navigation.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Replaces the previous "hide sidebar on admin" approach with a
composable compound component design. DS provides shell + building
blocks (Sidebar, Section, Footer, SidebarTree); consuming app
controls all content, section ordering, accordion behavior, and
icon-rail collapse.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>