Fork an existing world into your namespace — copy someone else's world as a starting point (GitHub-style). Pass source = the world_guid from zeromind.search { scope: 'worlds' } (a foreign world), or a name of one of your own worlds. The fork inherits the source's visibility (a fork of a public world is public — you can't privatise it), and a fork of a draft is a draft meant for the same visibility. Optional name overrides the default "-fork". Returns the new world_guid; open it with world.open { world: } and act on its next, then world.connect { world: } waits for the editor.