Implement isSystemInDarkTheme for desktop

[igordmn]

In Android target we can know if the system is in a dark mode using androidx.compose.foundation.isSystemInDarkTheme.

Probably we can implement it for desktop too. Some OS'es support dark mode.

P.S. if we will implement it, we should define "expect fun isSystemInDarkTheme" in the common code.

[tkuenneth]

Would be a great addition.

[ggoraa]

I agree. It will be very useful :D

[ggoraa]

Where we can track the progress of implementing isSystemInDarkTheme()?

[akurasov]

@igordmn, am I correct that isSystemInDarkTheme is working for desktop now?

[igordmn]

It works, but we still need to:

1. support Linux (Ubuntu at least)
2. observe theme changing

[dragossusi]

Gnome 42 added support for dark mode, it would be nice to detect it using this method

[rylexr]

Any progress on this? I tried it on MacOS, Ubuntu, and Windows and it's not working.

[long76]

look at this https://github.com/Dansoftowner/jSystemThemeDetector

[long76]

more link for linux https://unix.stackexchange.com/questions/701432/command-for-detecting-whether-the-system-is-using-a-dark-or-light-desktop-theme

telegramdesktop/tdesktop#17061

for linux just use org.freedesktop.appearance.color-scheme