feat: How about add light/dark theme mode?

[yurenchen000]

➊ editor theme follow app theme

• when app theme change between dark/light
  the editor theme also change with dark/light.

like something in Kate:

when i change color scheme (app theme) to a light/dark one,
the color theme (editor theme) auto changed

//Most of its editor themes include *-light and *-dark variations.

app dark

app light

And,

➋ app theme follow system theme

• when system change dark/light
  the app theme auto change with dark/light.

[yurenchen000]

i made it.
just works (on ubuntu22, gnome42)

Preview

liteide_auto_dark2.webm

New options

in editor options: a dark scheme for ➊ :

in app options: a dark theme for ➋:

Maybe a tab (or toggle button) for theme-mode signle-theme | light-dark-theme will better,
(i didn't tune the options UI, just make it work first)

like the theme settings in github

[yurenchen000]

if anyone want try it the code is here
master...yurenchen000:liteide:chen-add_theme_manager

currently

• ➊ editor theme follow app theme
  // all support maybe, when change app theme

• ➋ app theme follow system theme, currently it only support

  • linux with gnome, use gsettings monitor //tested on ubuntu22, gnome42, x11
  • win
  • mac

[yurenchen000]

how's it going

@visualfc