As an example, an old Android project of mine: https://github.com/moritzruth/JamRSSI showed one screen in both the light and the dark variant to demonstrate that the app generally has support for dark mode.
Where: In the repository, most projects seem to use media or screenshots as the name of the directory.How often: Whenever a big change happened or many small changes have accumulated.What: Light theme suffices. I only care about the general look and feel, not about specific colors.That’s how I would do it for my own projects.
Migadu is the best email hoster I know. I've been using them for all my emails during the last three years and never had an issue.They allow catch-all recipients and forwarding, so your use-case should be possible.
I’ve recently read that Affinity programs now work through Bottles, though I haven’t yet tried it myself.
As someone else already mentioned, using it with a trackpad (for example the Apple Magic Trackpad) is great.
Have you tried turning it off and on again?