handle card creation when can't create Basic+issues

Setup: Anyone doesn't have permission to create Basic, but does have permission to create one or more other cardtypes.

If you go to /new/card you're told you have to sign in first. If you go to /new/AllowedCardtype you get an offer to create a card of that type, with the right edit interface.

If you go to wagn/NonexistentCard you get an offer to create a card, with the type menu showing types that Anyone has permission for. However, you get the Basic edit interface rather than the multi-edit you should get when the menu shows a type with a hard-format.

Either we want going to wagn/NonexistentCard to tell you that you have to sign in first, or to generate the correct edit interface for whatever type is selected.