- AISidebar: full height, right of TopBar and Toolbar (all pages except AI Assistant)
- AISidebar: collapsed mode shows narrow 48px icon strip with KI button
- AISidebar: expanded mode uses ResizablePanel with drag-to-resize (240-600px)
- AppShell: moved AISidebar outside inner content container to full-height flex
- uiStore: renamed aiSidebarOpen→aiSidebarCollapsed (default: true=collapsed)
- TopBar: AI button highlights when sidebar is expanded