[Feature Request] Allow Changing PWA Accent / Theme Color

[amxmln]

When WebK is installed as a PWA, the accent colour / theme colour of the app seems to be derived from the current theme, but it often doesn’t match most of the window, especially in dark mode, making for a bit of a jarring experience.

I think the theme colour should match the main background color of the app window, or be customiseable by the user.

Lovely project! Thank you for your hard work.