message: add slots to position tracker
diff: @@ -669,6 +669,13 @@ class Robot(object):
  self._deck, *self._deck.coordinates()
  )
  + for slot in self._deck:
  + self.position_tracker.track_object(
  + self._deck,
  + slot,
  + *slot.coordinates()
  + )
  +
  @property
  def deck(self):
  return self._deck
  