Set up Next.js v15 starter kit with App Router architecture including:
- TailwindCSS v4 with CSS-based config and OKLCH color system
- shadcn/ui components (New York style) with Lucide icons
- next-themes for light/dark/system theme toggle (Korean labels)
- Layout components: navbar, footer, theme-toggle
- Import aliases and TypeScript configuration
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
