Thanks for such a speedy response, brach (and on the weekend, no less!). I believe the jumpers are soldered correctly. I bridged the two pads contained within the white rectangular outlines at JP1 – JP4. Just to make sure, I went ahead and reflowed the solder at each one and tested the pedal again; same result. I am able to tap out a rhythm with the tap tempo foot switch and the green LED pulses to match that tempo, so I believe the microcontroller is working.
I really appreciate you taking the time to help me troubleshoot!