This week I planned to work only on UI but got sidetracked by a bunch of stuff relating to autotools, unmerged GJS branches I was relying on, and the fact that I started classes again. So I didn't get as far as I wanted to in my UI implementation. Anyway, here are the results:
I have several bugs to fix next week and some features to re-implement, and some code clean-up, but in general I've finished everything except refreshing the UI when a file is added or deleted. I'm planning to just watch the directory with Gio.FileMonitor and just refresh the UI on changed, which shouldn't be too hard to implement.
I'm hoping to push the code to git.gnome.org as soon as it's cleaned-up - in a couple weeks - and release a preview of the app for unstable 3.11.