enterGroup method
Implementation
void enterGroup(String groupId) {
final group = store.scene.shapeById(groupId);
if (group?.source.type != Shapes.group) return;
final existingIndex = groupFocusPath.indexOf(groupId);
final nextPath = existingIndex >= 0
? groupFocusPath.take(existingIndex + 1).toList(growable: false)
: [...groupFocusPath, groupId];
setCanvasWorld(nextPath);
}