a gallery is a carousel

It always rendered as one — data-carousel, a snap track, two arrows, driven by
carousel.client.js. The entity was the last thing still calling it something
else, and that collided with the site's own Gallery section: two nav rows
reading Gallery and Galleries, meaning a list of objects and a list of
photograph sets.

GalleriesPanel, GalleryPicker and GalleryItems become Carousels*, the endpoint
becomes /fofos-admin/carousels, the block kind becomes carousel and
subject-gallery becomes subject-carousel. The publish allowlist follows the
renamed tables.

What did NOT move: GALLERY_CONFIG at /fofos-admin/gallery, subjects.ts's
base '/gallery', and home_gallery_media. Those are the Gallery section and the
legacy rows, and both are correct.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/DetailPanel.tsx

@@ -7,7 +7,7 @@ import { AdministrationPanel } from './AdministrationPanel';
 import { MediaPanel } from './MediaPanel';
 import { CollectionsPanel } from './sections/CollectionsPanel';
 import { PiecesPanel } from './sections/PiecesPanel';
-import { GalleriesPanel } from './sections/GalleriesPanel';
+import { CarouselsPanel } from './sections/CarouselsPanel';
 import { LayoutPanel } from './sections/LayoutPanel';
 import { PageBuilderPanel } from './sections/PageBuilderPanel';
 import { ViewModeProvider } from './ViewMode';
@@ -50,7 +50,7 @@ const PANELS: Partial<Record<SectionKey, () => React.JSX.Element>> = {
   layout: LayoutPanel,
   collections: CollectionsPanel,
   pieces: PiecesPanel,
-  galleries: GalleriesPanel,
+  carousels: CarouselsPanel,
   messages: MessagesPanel,
   administration: AdministrationPanel,
   media: MediaPanel,