Polish movement hall interiors: clear doors and bay columns, tone floors and windows.

Document hang keep-outs and period-module fixes; leave columns fixed while packing frames into gaps.

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

client/src/components/MovementHallDetails.tsx

@@ -1,6 +1,7 @@
 import { useMemo } from 'react';
 import type { MovementInteriorStyle, GalleryWindowSpec } from '../data/movement-interior-styles';
 import type { RoomDims } from './hall-details/geometry';
+import { bayPositions } from './hall-details/geometry';
 import {
   CinquecentoDetails,
   QuattrocentoDetails,
@@ -48,12 +49,7 @@ function GothicDetails({ width, depth, halfW, halfD, trim }: Omit<Props, 'style'
   // Compound piers along the side walls, spaced by bay, each rising into the
   // vault springer. Shafts stay flush against the wall (0.16 m proud) so they
   // never intrude on the ~0.7 m frame hang margin.
-  const bays = useMemo(() => {
-    const spacing = 4.2;
-    const count = Math.max(2, Math.min(9, Math.floor(depth / spacing)));
-    const step = depth / (count + 1);
-    return Array.from({ length: count }, (_, i) => -halfD + step * (i + 1));
-  }, [depth, halfD]);
+  const bays = useMemo(() => bayPositions(depth, halfD, 4.2, 9), [depth, halfD]);
 
   const shaftHeight = 3.5;