I removed the bulb from the interior dome light (to measure it to replace it with an LED bulb) and immediately put it back in. Now most of my electrical system doesn't work, including the interior dome lights, step lights, and automatic door locks. Any ideas what the problem might be?

 

You probably blew the DOME fuse (also check the other fuses), I think on your car it's under the hood, if not behind the coin tray. Either way check that fuse.

 

Come to think of it, that's probably what happened. I tried to put in a different bulb and saw a small spark.