Add public curator notes and U-shaped hall wall hang.

Paintings get editable curator notes with brass plates in the 3D hall, and visit order now uses the far/end wall between left and right.

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

Documentation/DB_structure.md

@@ -104,7 +104,8 @@ Phases within an artist’s career (e.g. “Blue Period”, “Roman Period”).
 | `period_id` | FK → `artist_periods` | Optional grouping |
 | `title` | VARCHAR(300) | |
 | `year`, `year_end` | INTEGER | Creation date(s) |
-| `description` | TEXT | |
+| `description` | TEXT | Wikipedia-style catalog text |
+| `curator_notes` | TEXT NOT NULL DEFAULT '' | Public curator editorial notes (inline edit on detail; brass plate in 3D hall when non-empty) |
 | `image_path` | VARCHAR(500) | Full-size local file; nullable after debug **Clear** |
 | `thumbnail_path` | VARCHAR(500) | Smaller variant for lists / 3D; nullable after **Clear** |
 | `wikipedia_title` | VARCHAR(300) | Used by image fetcher |
@@ -114,7 +115,7 @@ Phases within an artist’s career (e.g. “Blue Period”, “Roman Period”).
 
 When `checkup_fixed` is true, `checkup_checked` is set automatically and cannot be cleared until **Fixed** is off. A cleared painting (`image_path` and `thumbnail_path` both null, `checkup_fixed` true) is shown as an empty frame in detail view and is not refetched on demand.
 
-Applied by `npm run dev:migrate:checkup-flags` (`db/migrate-checkup-flags.sql`).
+Applied by `npm run dev:migrate:checkup-flags` (`db/migrate-checkup-flags.sql`). `curator_notes` is applied by `db/migrate-curator-notes.sql` via `npm run dev:migrate`.
 
 ### `painting_annotations`