favicon.svg now uses currentColor + prefers-color-scheme so a single
asset adapts to light/dark. Removed unused .ico/.png and 512 raster;
192 PNG kept and regenerated for apple-touch-icon and PWA maskable.
- Add service worker with caching for build assets, static files, images, and pages
- Add IndexedDB storage for recipes (brief and full data)
- Add offline-db API endpoint for bulk recipe download
- Add offline sync button component in header
- Add offline-shell page for direct navigation fallback
- Pre-cache __data.json for client-side navigation
- Add +page.ts universal load functions with IndexedDB fallback
- Add PWA manifest and icons for installability
- Update recipe page to handle missing data gracefully