[twisty] Significantly decrease the camera frustrum far distance.

In practice, we only need about 10.
20 should allow zooming out a moderate amount.

src/cubing/twisty/dom/viewers/Twisty3DCanvas.ts

@@ -91,7 +91,7 @@ export class Twisty3DCanvas
       20,
       1, // We rely on the resize logic to handle this.
       0.1,
-      1000,
+      20,
     );
     this.camera.position.copy(
       options.experimentalCameraPosition ?? new Vector3(2, 4, 4),