You can do this if you shift from using regular lists to using tags and smartlists, as there is a tagcontains search command.

No, there's currently not a way to search for tasks that way.

What you could do is keep your lists (optionally without the "wk-" prefix), tag all the tasks therein with "wk" or "work", then search for tag:work and you'll get all of them, no matter in which list they appear.

There are other ways of organizing that way, but that one's probably the simplest. Let me know if you'd like others.