Wth!? (dashboard dead after headliner removal...?)

My 2006 failed to start this morning! I mean, no dashboard lights at all, even with a jumper cable connected to another car!!

<24 hours earlier...>
I finally decided to take on the headliner removal, so that I could replace the antenna with an antenna for my mobile ham rig. The grab bar clips were a huge PITA. I took pictures of the tool I used and some tips to post on Prius chat.I got all the other plastic parts, dome lights, etc. out and stashed in ziploc bags.
I was proud of myself.
Getting the headliner off the top of the B and C pillars was hard. I didn't want to damage the liner. I decided to leave it in place and deal with it tomorrow. Then I found the excellent writeup by @charliehoward so I was optimistic that the end was in sight.

Now, the dashboard is completely unresponsive. I can hear the brake actuator pumps buzzing from time to time, and they buzz when I step on the brake. Otherwise there is NO response to the start button!
Could I have blown a fuse or something?
Does anyone know where I should begin to look?
I have to admit, I have never read of anyone trying to drive the car when the domelights are disconnected... is there some kind of safety switch that I need to deal with?

 

That makes perfect sense... un-f@#%-believable. Thank you sire, you're a gentleman and a scholar.

 

Here are some pics I took to help the next guy who runs into this...