Add movement artist filter modal and fix large-hall texture blanks

Clicking a movement opens ArtistFilterModal to choose artists before the gallery. Large halls no longer permanently blank frames when texture loads exceed the overlay deadline; fall back thumb to full to on-demand API.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/api/client.ts

@@ -5,6 +5,7 @@ import type {
   Artist,
   ArtistDetail,
   MovementGalleryDetail,
+  ArtistSummary,
   Painting,
   PaintingDetail,
   ArtistNavigation,
@@ -176,6 +177,30 @@ export function galleryImageUrl(
   return null;
 }
 
+/** Ordered texture URL candidates for a hall frame (thumb → full → on-demand API). */
+export function galleryImageUrlCandidates(
+  painting: {
+    id?: number;
+    thumbnail_path?: string | null;
+    image_path?: string | null;
+    image_cache_key?: number | null;
+    thumbnail_cache_key?: number | null;
+  },
+  sessionRevision?: number | null
+): string[] {
+  const revision = paintingImageRevision(painting, sessionRevision);
+  const urls: string[] = [];
+  const push = (u: string | null | undefined) => {
+    if (u && !urls.includes(u)) urls.push(u);
+  };
+  if (painting.thumbnail_path) push(imageUrl(painting.thumbnail_path, revision));
+  if (painting.image_path) push(imageUrl(painting.image_path, revision));
+  if (painting.id != null) {
+    push(`/api/paintings/${painting.id}/image?size=thumb`);
+  }
+  return urls;
+}
+
 export function galleryImageUrlWithRevision(
   painting: {
     id?: number;
@@ -458,6 +483,9 @@ export const api = {
 
   getMovementGallery: (id: number) => fetchJson<MovementGalleryDetail>(localizedPath(`${API}/movements/${id}/gallery`)),
 
+  getMovementArtistsSummary: (id: number) =>
+    fetchJson<ArtistSummary[]>(localizedPath(`${API}/movements/${id}/artists-summary`)),
+
   getArtistNavigation: (id: number) =>
     fetchJson<ArtistNavigation>(localizedPath(`${API}/artists/${id}/navigation`)),