Albumen 1.1

New since v1.01:
- Auto-transcode non-browser-playable video formats (AVI/MKV/MOV → MP4)
- Hide transcoded originals from non-admins; mark them visually for admins
- Per-photo delete checkbox in admin edit form
- Folder rename in admin edit form
- Background update with streaming progress log
- Browser upload (multi-file, up to 2 GB) with upload progress bar
- Update skips unchanged directories via sentinel file
- Viewport-filling media in lightbox and slideshow (object-fit: contain)
- Hover zoom preview for admin thumbnails
- Slideshow button shown for folders with media anywhere in hierarchy
- OG/social preview image; favicon and apple-touch-icon
- albumen.png as app icon and OG fallback