Automatically select light/dark theme based on `color-palette-update-notifications`

**Is your feature request related to a problem? Please describe.**
> Most modern operating systems and desktop environments do support Dark and Light themes, this includes at least MacOS, Windows, KDE Plasma, Gnome, and probably others.
>
> Some even support switching from dark to light and light to dark mode based on sun rise / sun set.
>
> In order to not make the terminal emulator look bad after such switch, we must enable the applications inside the terminal to detect when the terminal has updated the color palette. This may happen either due to the operating system having changed the current theme or simply because the user has explicitly requested to reconfigure the currently used theme (e.g. because the user requested to change the terminal profile, also containing a different color scheme).

**Describe the solution you'd like**
Adopt the [`color-palette-update-notifications` standard](https://github.com/contour-terminal/contour/blob/master/docs/vt-extensions/color-palette-update-notifications.md).

**Describe alternatives you've considered**
All other solutions are kinda bad. It's good that we finally have a standard for this.

**Additional context**
Already supported by Ghostty, Kitty, Neovim, Tmux.
WezTerm, Zellij, and Helix are adding support at the moment.