Horizon mapping cleanup and bugfixes (#21450)

Fixes https://github.com/Aurorastation/Aurora.3/issues/21289
Fixes https://github.com/Aurorastation/Aurora.3/issues/15779

Handles a lot of mapping cleanup, container definitions for the Horizon,
and several bugfixes found along the way.

changes:
- code_imp: "Added set definitions for several Horizon-specific
containers."
- code_imp: "Updated 'full' material stacks on the Horizon from sneaky
var-edited singles to properly defined full stacks"
- code_imp: "Cleaned up all Air Alarms, Fire Alarms, and APCs on the
Horizon that were directional children with their dir var edited."
- code_imp: "Cleaned up all Power Cables on the Horizon that had d1 or
d2 var edited instead of just icon_state."
- code_imp: "Adjusted pixel shifts for 'south' (north-facing) Air
Alarms, Fire Alarms, APCs, and Extinguisher Cabinets to address layering
issues when standing vs. leaning."
- code_imp: "Minor refactor of shuttle/* Air Alarms and APCs to reduce
excess children; req_one_access perms now assigned based on
/area/horizon/shuttle/*."
  - qol: "Adds feedback hint for uses remaining to Emag cards."
- qol: "Added Tip about the shift-click behavior of the 'up-hint'/'Look
Up' button."
- bugfix: "See-through turfs (like lattices/catwalks over open space)
can now be Looked Up through from below."
- bugfix: "Fixed the shift-click behavior of 'up-hint'/'Look Up' button,
allowing you to see nearby turfs that can be Looked Up through."
- bugfix: "Maintenance Panels located on the floor have had their
layering issues fixed."
- bugfix: "Borg eye emissive effects MAYBE no longer visible through
higher z-levels."
- bugfix: "Added missing leanable component to window/shuttle obj type."

code/modules/mob/living/carbon/human/human_movement.dm

@@ -138,9 +138,9 @@
 			footsound = T.footstep_sound
 
 	if (client)
-		var/turf/B = GET_TURF_ABOVE(T)
+		var/turf/T1 = GET_TURF_ABOVE(T)
 		if(up_hint)
-			up_hint.icon_state = "uphint[(B ? !!B.is_hole : 0)]"
+			up_hint.icon_state = "uphint[(T1 ? !!isopenturf(T1) : 0)]"
 
 	if (!stat && !lying)
 		if ((x == last_x && y == last_y) || !footsound)

code/modules/mob/living/silicon/robot/robot_helpers.dm

@@ -33,7 +33,7 @@
 		return
 	var/eye_plane = src.plane
 	if(lights_on && layer == MOB_LAYER) // in case you're hiding. so eyes don't go through tables.
-		eye_plane = EFFECTS_ABOVE_LIGHTING_PLANE //make them glow in the dark if the lamp is on
+		eye_plane = MOB_EMISSIVE_LAYER //make them glow in the dark if the lamp is on
 	var/eyeprefix = module_sprites[icontype][ROBOT_EYES]
 	if(speed == -2) // For combat drones with the mobility module.
 		cached_eye_overlays = list(