Accent color in dark mode

[jocmp]

One thing I miss though is the color bar on the left of the Article List. This color is auto-generated, I guess from the main color of the favicon of the feed.
Probably not something to add by default, maybe not everyone would like it, but I would definitely enjoy having such option.
What do you think?

Illustrative screenshot of the Nextcloud News Android app:

Originally posted by @alxrdn in #1751

[jocmp]

2026.03.1199