fix: unable to ./docker-run.sh on Wayland

[rgon]

The docker-run.sh command forwards the X11 sockets, but since all the environment variables say it's running on Wayland, the Qt platform runs expecting to be able to access it. As it can't, it errors out.

This patch overrides the XDG_SESSION_TYPE environment variable to x11, forcing xwayland usage on Wayland systems while keeping compatibility with x11.

Fixes #160