- Zustand sidebar store with persist middleware (collapse/expand, mobile open)
- Sticky header with logo, breadcrumb, theme toggle, locale switcher, user avatar
- Collapsible sidebar with Dashboard/Marketplace nav, accordion categories, footer
- Mobile responsive: hamburger menu with overlay sidebar on small screens
- Theme toggle cycling light/dark/system with mounted guard
- Locale switcher setting NEXT_LOCALE cookie with router.refresh
- Empty dashboard state with grid icon, "Keine Widgets aktiv" text, add button
- AppShell composing header + sidebar + responsive main content area
- All user-visible strings via useTranslations (UI-03 compliance)
- OKLCH design tokens with yellow #ffed00 primary and dark gray-blue dark mode
- next-intl cookie-based locale with DE/EN message files
- next-themes provider with system/light/dark support
- Sidebar and header layout dimension tokens
- Root layout with ThemeProvider and NextIntlClientProvider wrappers
schalli