Reckless! I re-fixtured my lovely circuit (the only complete circuit I've made so far) and carved in another set of pads to suit an ESP32C3 XIAO module from Seeed Studio. I flashed a fresh Micropython bootloader and wrote a few lines to fill the shift register with 1s and 0s with 0.5 s delays.

It works!

For now, sleep; but to come, more images, some notes on the design workflow, a video of fabrication (carving on the same board as a bunch of soldered parts, ack!), a bit of code, a discussion on the various repairs and bodges it took to get here, a love letter to 34 AWG polyurethane-insulated magnet wire, etc.