Sidebar

Layout primitives for the catalog-style left rail every Rahhal mini-app uses: a glassy floating column with a sticky filter / brand area, a scrolling body, and collapsible sections. Pair `<AppSidebar>` with `<AppSidebarHeader>`, `<AppSidebarBody>`, `<AppSidebarSection>`, `<AppSidebarItem>` (and optional `<AppSidebarFooter>`). The chrome is layout-only — apps supply data, routing, and filtering. For mobile, render the same content inside a `<Sheet>` and add a hamburger button to `<AppHeader>`.