- Created admin authentication system with useIsAdmin hook
- Added AdminProtected component for route protection
- Added prominent 'Edit Card (Admin)' button on card detail pages
- Protected all admin routes (/admin/*) with authentication
- Added admin navigation item to main layout sidebar
- Updated auth verification API to return mock admin user
- Integrated admin edit button that redirects to card editor with card ID
- Added proper access denied page for non-admin users
- Admin-only features now show/hide based on user role
- Seamless workflow: spot incorrect card → click edit → fix immediately
