The Cockpit display portal publishes the Display popover's slots to the
gev-display store while Cockpit is on, and the Display panel teleports its
HUD, Detection, Parameters and 3D groups into them and back, each only
while its own slot is published. The portal no longer moves the groups:
it keeps each surface's scroll position, puts back focus the move
dropped, and lays the surfaces out once Vue has moved them. The popover's
uses-shared-display-controls class renders from the store, and the right
rail no longer re-homes the parameters panel the markup already places.