Add movement gallery wings with period interiors and expand timeline features.

Movement galleries split large catalogs into chronological wings (~55 works), use era-themed 3D interiors with side-wall windows, wing navigator on the back exit, and front archways between wings. Also adds painting annotations, timeline event guides, portrait hover highlights, and documentation/API updates.

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

db/migrate-painting-annotations.sql

@@ -0,0 +1,18 @@
+-- Short art-history annotations on painting detail (with optional image markers)
+CREATE TABLE IF NOT EXISTS painting_annotations (
+  id SERIAL PRIMARY KEY,
+  painting_id INTEGER NOT NULL REFERENCES paintings(id) ON DELETE CASCADE,
+  label VARCHAR(80),
+  body TEXT NOT NULL,
+  category VARCHAR(30) NOT NULL DEFAULT 'subject',
+  pos_x NUMERIC(5, 2),
+  pos_y NUMERIC(5, 2),
+  source_author VARCHAR(200),
+  source VARCHAR(500),
+  source_url VARCHAR(500),
+  sort_order INTEGER NOT NULL DEFAULT 0,
+  confidence VARCHAR(20) NOT NULL DEFAULT 'curated'
+);
+
+CREATE INDEX IF NOT EXISTS painting_annotations_painting_idx
+  ON painting_annotations (painting_id);