I opened up the lock mechanism assembly. Here is a picture.
The switches both looked like there were in proper physical position and condition. I suppose I would need to test them for continuity in order to know for sure what the situation is.
EDIT: OK, I hacked a semi-permament fix.
With the door open and the latch swinging open to closed, I timed the latch as it swung back and forth and noticed that it ran on a 30 second interval, fully open at zero and fully closed at 30 seconds.
I turned the breaker off when it was on its second cycle of fully open (at 60 seconds). I then came upstairs and verified the latch was fully open (it was). Then, I turned the breaker back on.
I went upstairs and turned on the oven t-stat and set the oven to bake, and then convection and broil modes. The "door locked" light stayed off and the latch was not swinging back and forth. SUCCESS!
This doesn't fix the problem that the oven doesn't unlock after being put into clean cycle, but it does give me access to use the oven again. If you're willing to help me troubleshoot a permanent fix, I'm up for it. It would seem to be a matter of testing for voltage at the right time and in the right places . . .