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>

server/index.js

@@ -335,6 +335,29 @@ app.get('/api/movements/:id/gallery', async (req, res) => {
   }
 });
 
+// Artists for a movement with painting counts (for gallery entry filter modal)
+app.get('/api/movements/:id/artists-summary', async (req, res) => {
+  try {
+    const { id } = req.params;
+    const result = await pool.query(
+      `SELECT a.id, a.name, a.birth_year, a.death_year, a.portrait_path, a.portrait_thumb_path,
+              COUNT(p.id)::int AS painting_count
+       FROM artists a
+       LEFT JOIN paintings p ON p.artist_id = a.id
+       WHERE a.movement_id = $1
+       GROUP BY a.id
+       ORDER BY a.birth_year NULLS LAST, a.name`,
+      [id]
+    );
+    const { locale, statuses } = localeContext(req);
+    const localized = await localizeArtists(result.rows, locale, statuses);
+    res.json(localized.map(enrichArtistRow));
+  } catch (err) {
+    console.error(err);
+    res.status(500).json({ error: 'Failed to fetch movement artists summary' });
+  }
+});
+
 // Artists for a movement in a time range
 app.get('/api/movements/:id/artists', async (req, res) => {
   try {