Updates from 2025-10-25 (1c3cf95d)

Added support for dark theme (with stock UIKit colors), with a switch button in the footer.
Added an "NSFW" systag (and corresponding label), allowing images and videos to be marked with it, which causes them to appear blurred until clicked. Useful for making sure sensitive content isn't flashed to users who might not want to see it.
Started experimenting with more advanced media editing, having added features to respectively trim and join videos.