This change has substantially bumped up the daemon's overall robustness,
as the code now ensures that the controller will only start once the
/dev/input/eventXX file is set up, which was causing all sorts of issues
in the past.
Additionally, this change enables the daemon to run as a proper
background task that _doesn't_ constantly die / need to be restarted,
which removes the need for any janky udev "on add" rules, and instead, a
simple systemd user service will suffice.
