Improve timeline UX and add catalog restore scripts for paintings and portraits.

Load the home-page catalog once with a lightweight artists API, batch pan/zoom updates per frame, use dynamic year labels, and speed up movement-flow zoom. Add sync-image-paths and fetch-artist-images plus docs for the post-seed pipeline.

client/src/api/client.ts

@@ -174,6 +174,9 @@ export const api = {
     return fetchJson<Artist[]>(`${API}/artists?${params}`);
   },
 
+  /** Lightweight artist rows for the timeline (no biography text). */
+  getTimelineArtists: () => fetchJson<Artist[]>(`${API}/artists?timeline=1`),
+
   getArtist: (id: number) => fetchJson<ArtistDetail>(`${API}/artists/${id}`),
 
   getMovementGallery: (id: number) => fetchJson<MovementGalleryDetail>(`${API}/movements/${id}/gallery`),