Smooth 3D hall boot: disable shadows and warm door shaders under the loading overlay.

Keep Loading gallery until Environment and gl.compileAsync finish (with timeouts), GPU-upload painting textures before dismiss, and drop Canvas shadow maps.

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

client/src/components/GalleryWindows.tsx

@@ -181,7 +181,6 @@ function SingleWindow({
         intensity={spec.lightIntensity}
         distance={14}
         color={spec.lightColor}
-        castShadow={false}
       />
       <pointLight
         position={[0, 0, 0.25]}
@@ -250,7 +249,6 @@ export function GalleryTrackLights({
             intensity={intensity}
             distance={8}
             color={color}
-            castShadow={false}
           />
         </group>
       ))}