Photographers running the gallery as a client-selection tool want to
map a guest's picks back to source files for retouching. The
`general_use_original_filenames_for_downloads` toggle (#493) already
does this on the download side; this extends the same toggle to the
in-lightbox view so the camera filename is visible alongside the
photo while it's being looked at.
Tied to the same toggle on purpose — one switch controls both
surfaces. Off by default; existing galleries keep showing only the
position counter.
Wiring:
- gallery.js serializes `photos[].original_filename` and surfaces the
resolved toggle as `event.use_original_filenames` so the client can
decide whether to render it.
- The bespoke `PhotoLightbox` renders the original filename (falling
back to the storage filename only for pre-migration-062 uploads) in
a muted line under the position counter, truncated to keep the
toolbar tidy.
- `GalleryStoryLayout` mounts the same `PhotoLightbox`, so its
rendering follows along.
- `GalleryPremiumLayout` uses `yet-another-react-lightbox` instead;
added the Captions plugin and a `title` field on the slides so the
same name appears as a caption when the toggle is on.
The remaining layouts feed back into the main `PhotoLightbox` via
`PhotoGridWithLayouts`, so the prop reaches them through the layout
props bag.
Paul Nothaft
33de294d57