Set `XDG_STATE_HOME`

From the [xdg basedir spec](https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html):

> $XDG_STATE_HOME defines the base directory relative to which user-specific state files should be stored. If $XDG_STATE_HOME is either not set or empty, a default equal to $HOME/.local/state should be used.
>
> The $XDG_STATE_HOME contains state data that should persist between (application) restarts, but that is not important or portable enough to the user that it should be stored in $XDG_DATA_HOME. It may contain:
>
> - actions history (logs, history, recently used files, …)
>
> - current state of the application that can be reused on a restart (view, layout, open files, undo history, …)

I’m not entirely sure what it should be set to as I’m not familiar with iOS development, probably a folder inside `~/Library`

This is needed for [ani-cli](https://github.com/pystardust/ani-cli/issues/1350)