I finally tracked down the source of the problem with the screen: with the repeated removal and insertion into the case, the glass of the LCD basically cut the ribbon cable that connects it to the PCB. Unfortunately, it did so in a way that's not reparable, so the watch is screenless until mid-November when I can get a replacement.

On the plus side, I made some software progress, including scaffolding that will let me run a version of the watch code on Linux. This means that I can at least continue work on the interface while I wait.

The rest of the PCB works well enough, so I can use that to test my BLE code in the meantime. I can still make progress on the project, but it's immensely unsatisfying to do so without being able to wear the result.

The repository is a bit of a mess, but you can check it out here.