Description

Set up shadcn/ui components and theming system.

Tasks

• Install and configure shadcn/ui using official CLI
• Install next-themes for theme management
• Set up base layout with theme provider
• Configure global styles and CSS variables
• Verify dark/light mode switching works

Acceptance Criteria

• shadcn/ui CLI successfully installed components
• Theme switching works (dark/light mode)
• Global styles applied correctly
• CSS variables configured for theming

Technical Notes

• Use shadcn/ui CLI: npx shadcn-ui@latest init
• Configure for Next.js app router
• Set up Tailwind CSS properly
• Test theme persistence

Related TODO.md lines: 22, 27, 32-33