Add lazy loading with skeleton animations and IndexedDB-based image caching to improve thumbnail loading performance. The changes include:
- CSS animations for loading states with shimmer effects
- Priority-based image loading queue with configurable concurrency
- Persistent image cache with automatic cleanup
- Error handling and cached image highlighting
- Increased concurrent loading from 3 to 6 for faster initial display
This reduces network requests and provides smoother user experience when browsing large model collections.
- Add horizontal scroll to thumbnail rail on wheel event
- Add wheel-based image navigation in main image area (150 threshold)
- Add image counter showing current position (e.g., "1 / 12")
- Use tabular-nums and min-width: 2ch to prevent counter layout shift
- Respect params panel scrolling when using wheel navigation
- Add preloadMedia() for async image/video loading before display
- Implement renderLoadingSkeleton() with fa-circle-notch fa-spin animation
- Add fadeIn transition (opacity 0→1) for main media elements
- Remove shimmer gradient animation from thumbnails for cleaner look
- Use solid background color placeholder with subtle fade-in for thumbnails
- Fixes progressive rendering of remote images from top to bottom
- Prevents black flash during loading with proper loading states
- Add showcase__nsfw-notice-content wrapper for better layout
- Add showcase__nsfw-show-btn with styling matching card.css show-content-btn
- Add show-content action handler that triggers global blur toggle
- Button uses blue accent color with eye icon and hover effects
- Clicking Show button syncs with blur toggle button icon state
- Use unique class names to avoid conflicts with card.css
