Features added:
- Leftover media management page in admin panel with delete functionality for images and videos
- Individual file delete buttons for leftover media
- PDF to PNG conversion (each page becomes a separate image at Full HD resolution)
- Delete functionality for leftover video files
- Enhanced playlist management with duration editing for all content types
- Improved dark mode support for playlist management page
- Content type badges with color coding
- Better styling for duration input fields with save functionality
- Fixed URL generation for duration update endpoint
