Blanking the only live output in dock mode led to a brick where wake and
even VT switch failed. Skip hypridle's 10m dpms off when any laptop
internal (eDP/LVDS/DSI) is present but not enabled; lock at 5m remains.
Undocked still blanks. Document LATER revisit for intentional
DPMS-when-docked once wake is proven.
V1: nix flake check --no-build. V3: docked idle stays lit under lock.