Per-host gate. Defaults to true; authors override to reject specific items (a fragile shelf rejects heavy items; a sloped surface rejects round items; a wax tabletop rejects hot items).
Items currently resting on this surface. Computed lazily by
walking the surface's environment and filtering by
Containable.getRestingOn() === this. Returned readonly;
mutate via ContainmentApi.placeOn / ContainmentApi.move.
MQL keyword bridge. If set, put X on <keyword> resolves the
keyword against the host's Detailed map and lands on this
surface. Mirrors SlotSpec.userFacingDetail
(see slot.md § Detail-targeted resolution).
Public shape provided by SurfacedMixin.