Fix harmonize prod DB targeting and large-hall loading hangs.

Prod env files now win over root .env so harmonize:db can open gallery_prod after gallery_dev; tour_stops gains updated_at; halls no longer block the overlay on every painting texture. Docs cover the fixes and one-artist image pull from prod; Duccio painting assets synced from TrueNAS.

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

db/migrate-tours.sql

@@ -20,9 +20,13 @@ CREATE TABLE IF NOT EXISTS tour_stops (
   painting_id INTEGER NOT NULL REFERENCES paintings(id) ON DELETE CASCADE,
   sort_order INTEGER NOT NULL DEFAULT 0,
   body TEXT NOT NULL DEFAULT '',
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
   UNIQUE (tour_id, painting_id)
 );
 
+-- Existing DBs created before updated_at: migrate-sync-timestamps.sql also adds it.
+ALTER TABLE tour_stops ADD COLUMN IF NOT EXISTS updated_at TIMESTAMPTZ NOT NULL DEFAULT now();
+
 CREATE INDEX IF NOT EXISTS tour_stops_tour_idx ON tour_stops (tour_id, sort_order);
 CREATE INDEX IF NOT EXISTS tour_stops_painting_idx ON tour_stops (painting_id);
 
@@ -38,3 +42,8 @@ DROP TRIGGER IF EXISTS tours_updated_at ON tours;
 CREATE TRIGGER tours_updated_at
   BEFORE UPDATE ON tours
   FOR EACH ROW EXECUTE PROCEDURE tours_touch_updated_at();
+
+DROP TRIGGER IF EXISTS tour_stops_updated_at ON tour_stops;
+CREATE TRIGGER tour_stops_updated_at
+  BEFORE UPDATE ON tour_stops
+  FOR EACH ROW EXECUTE PROCEDURE tours_touch_updated_at();