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.

Documentation/API.md

@@ -65,9 +65,12 @@ Artists for timeline portraits and the movement flow diagram.
 | `start` | int | Only artists alive after this year |
 | `end` | int | Only artists born before this year |
 | `movement_id` | int | Filter by movement |
+| `timeline` | bool | When `1` or `true`, return a lightweight row set for the home-page timeline (omits `bio_full` and other heavy fields) |
 
 **Response** — array of artist objects with joined `movement_name` and `movement_color`.
 
+The React home page loads the timeline catalog **once** on mount via `GET /api/bounds`, `GET /api/timeline?start=…&end=…` (full range), and `GET /api/artists?timeline=1`. Pan and zoom filter movements and portraits **client-side** — no refetch per view change. Rapid pan/zoom is batched with `createViewChangeScheduler()` (one React update per animation frame).
+
 ---
 
 ## `GET /api/movements/:id/artists`
@@ -581,6 +584,7 @@ The React client wraps these endpoints in `client/src/api/client.ts`:
 | `api.getBounds()` | `GET /api/bounds` |
 | `api.getTimeline(start, end)` | `GET /api/timeline` |
 | `api.getArtists(...)` | `GET /api/artists` |
+| `api.getTimelineArtists()` | `GET /api/artists?timeline=1` |
 | `api.getArtist(id)` | `GET /api/artists/:id` |
 | `api.getArtistNavigation(id)` | `GET /api/artists/:id/navigation` |
 | `api.getPainting(id)` | `GET /api/paintings/:id` |