Sadly the uncompressed PNG will bloat the repository forever, but at
least shallow clones should be better.
I ran oxipng[1] on it, which losslessly reduced it from 3.6 MiB down to
72 KiB.
Fixes a regression from both b51721ce79
and 8cc134e1d6. Actually if possible it
would be better to force-push to replace these two commits with this
version, and then ask the fdo admins to prune the repository.
[1] https://github.com/oxipng/oxipng
The `View` sturct was mostly a layer of indirection, and the controller benefitted by absorbing the gtk::Application
subclass parts, so now those two are merged into a new gtk::Application subclass.
The pipewire loop now runs without interruption in a second thread and communicates with
the GTK thread via a channel in each direction, instead of checking for events once a second and using callbacks.
This allows changes to appear instantly in the view, instead of having to wait.
The new architecture.md file contains a birds-eye overview of the top-level architecture
using box-drawing characters, but does not go into detail yet.
