Add guided tours and unify left-to-right hall wall hang.

Visitors walk published tours in a 3D hall with stop notes; curators edit drafts via Tour editor. All galleries (artist, movement, tour) place the first work left of the entrance view and the last on the right.

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

Documentation/DB_structure.md

@@ -136,6 +136,33 @@ Short art-history notes shown on painting detail (`PaintingAnnotations.tsx`).
 
 Applied by `npm run dev:migrate:painting-annotations` (`db/migrate-painting-annotations.sql`). Load data with `npm run dev:update-painting-annotations` (curated entries in `scripts/painting-annotations-data.js`; add `--wikipedia` for intro sentences from each work’s `wikipedia_title`).
 
+### `tours` / `tour_stops`
+
+Curated guided tours. See [tours.md](tours.md).
+
+**`tours`**
+
+| Column | Type | Notes |
+|--------|------|-------|
+| `id` | SERIAL PK | |
+| `title` | VARCHAR(200) | |
+| `description` | TEXT | Default `''` |
+| `status` | VARCHAR(20) | `draft` \| `published` |
+| `cover_painting_id` | FK → `paintings` | ON DELETE SET NULL |
+| `created_at` / `updated_at` | TIMESTAMPTZ | `updated_at` via trigger |
+
+**`tour_stops`**
+
+| Column | Type | Notes |
+|--------|------|-------|
+| `id` | SERIAL PK | |
+| `tour_id` | FK → `tours` | ON DELETE CASCADE |
+| `painting_id` | FK → `paintings` | ON DELETE CASCADE; UNIQUE with `tour_id` |
+| `sort_order` | INTEGER | Visitor / editor order |
+| `body` | TEXT | English tour notes for the stop (v1) |
+
+Applied by `npm run dev:migrate` (`db/migrate-tours.sql`).
+
 ### `painting_influences`
 
 Directed edges: *this painting* was influenced by *that painting*.