Overmap Layering (#16307)

code/modules/overmap/overmap_object.dm

@@ -15,6 +15,8 @@
 	var/generic_object = TRUE //Used to give basic scan descriptions of every generic overmap object that excludes noteworthy locations, ships and exoplanets
 	var/static_vessel = FALSE //Used to expand scan details for visible space stations
 
+	layer = OVERMAP_SECTOR_LAYER
+
 	var/list/map_z = list()
 
 	var/known = 0		//shows up on nav computers automatically

code/modules/overmap/ships/landable.dm

@@ -9,6 +9,7 @@
 	var/status = SHIP_STATUS_LANDED
 	icon_state = "shuttle"
 	moving_state = "shuttle_moving"
+	layer = OVERMAP_SHUTTLE_LAYER
 
 /obj/effect/overmap/visitable/ship/landable/Destroy()
 	shuttle_moved_event.unregister(SSshuttle.shuttles[shuttle], src)

code/modules/overmap/ships/ship.dm

@@ -22,6 +22,8 @@ var/const/OVERMAP_SPEED_CONSTANT = (1 SECOND)
 	generic_object = FALSE
 	var/moving_state = "ship_moving"
 
+	layer = OVERMAP_SHIP_LAYER
+
 //RP fluff details to appear on scan readouts for mobile objects.
 	var/propulsion = "Chemical Composite Gas Thrust" 	//Slower than light propulsion method. No variation in this currently exists yet except the Horizon which heats its gas.
 	var/drive = "None equipped, FTL incapable" 			//Faster than light propulsion method, will usually be warp drives for third party ships and nothing for shuttles