feat: editor improvements and collapsible sidebars

Add collapse/expand toggle for the AppShell navigation sidebar and the
editor properties panel (both persisted to localStorage). Bundles other
in-progress editor work including position anchors, outlet sizing, PBR
textures, window slope/frame depth, curtain metadata, and various 2D/3D
rendering tweaks.

apps/client/src/components/editor/layers/WallLayer.tsx

@@ -1,5 +1,5 @@
 import { memo, useMemo } from 'react';
-import { Layer, Line, Group } from 'react-konva';
+import { Line, Group } from 'react-konva';
 import type { Point, Wall } from '@house-plan-maker/shared';
 import { polygonCentroid } from '../utils/geometry';
 
@@ -163,7 +163,7 @@ export const WallLayer = memo(function WallLayer({
   }, [walls, selectedIds, zoom, panOffset]);
 
   return (
-    <Layer>
+    <Group>
       {/* Room interior fill */}
       {roomShapeScreen.length >= 6 && (
         <Line
@@ -231,6 +231,6 @@ export const WallLayer = memo(function WallLayer({
           listening={false}
         />
       ))}
-    </Layer>
+    </Group>
   );
 });