X11 runner

Configures the minimal X11 prerequisites used by the kiosk workflow. Modes are preflight, apply, and disable.

Install the X11 prerequisite layer

wget -qO- https://devs-guide.github.io/debian/setup/cli/x11.sh | \
  env DEBIAN_X11_MODE=apply \
      DEBIAN_X11_ENABLE=1 \
      DEBIAN_X11_INSTALL_PACKAGES=1 \
      bash

Variable	Purpose
`DEBIAN_X11_MODE`	Uses `preflight`, `apply`, or `disable`.
`DEBIAN_X11_ENABLE`	Explicitly enables or disables the managed X11 feature.
`DEBIAN_X11_INSTALL_PACKAGES`	Allows this runner to install its X11 package set during apply.
`DEBIAN_X11_PACKAGES`	Optional explicit package-list override; leave unset unless the host policy requires a reviewed change.

Use it independently for a narrow X11 setup or let kiosk.app.sh orchestrate it as part of a managed kiosk profile.