Add catalog search on timeline header and fix Back to Timeline navigation.

Public GET /api/search over artists, movements, and paintings with a debounced header bar on the timeline; Back to Timeline resets zoom and gallery session.

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

server/migrate.js

@@ -12,6 +12,7 @@ const INCREMENTAL_MIGRATIONS = [
   'migrate-auth.sql',
   'migrate-portrait-thumbs.sql',
   'migrate-perf-indexes.sql',
+  'migrate-search.sql',
 ];
 
 async function bootstrapCurator() {