Manifest ghost visibility-toggle

Ghosts which have been made visible by cultists can afterward turn themselves (in)visible at will, with a cooldown before being able to turn themselves visible after having faded from sight.

Maybe I'm just odd but I've felt it'd often be possible to build up a better mood if I didn't fly around visible everywhere, in particular when wanting to jump to certain conversations. With this it'd be possible to jump to a group of scared crew members, find a dark corner, or perhaps a door to walk through, and then turn visible when the moment is right.