Stupid question: does my rear derailleur have a hanger? I don't see it. The place where it should be seems to be part of the frame. If not, why not?
The hanger is part of the frame in this case. This is a pretty common design, though many newer frames will have the hanger as a removable part of the frame that can be replaced if damaged. In the case of your bike, if there is damage, you have to (carefully) bend it back to shape.