Add explicit stairs and measure elevator congestion with real actors

scripts/ui/pixel_tower_demo.gd

@@ -31,26 +31,26 @@ func prepare(runtime: Variant, clock: Variant, tree: SceneTree) -> bool:
 		return false
 	for facility: Dictionary in _runtime.construction_service.get_facilities():
 		facility_ids[facility[&"definition_id"]] = facility[&"instance_id"]
-	# Four rooms sit on the completed reception and dining structure. Corridor
-	# cells are ordinary supported construction; unfinished elevator topology is
-	# deliberately excluded from this scenario.
+	# Four rooms sit on the completed reception and dining structure. One
+	# continuous, paid staircase in the center joins all three upper landings;
+	# same-floor corridor construction links the rooms on either side.
 	for x: int in [-8, -6, 2, 4]:
 		if not _build(&"standard_room", Vector3i(x, 2, 0)):
 			return false
 	for x: int in range(-4, 2):
-		if not _build(&"guest_corridor", Vector3i(x, 1, 0)):
+		if not _build(&"guest_stairs" if x == -4 else &"guest_corridor", Vector3i(x, 1, 0)):
 			return false
 	if not await advance(60):
 		return false
 	for x: int in range(-4, 2):
-		if not _build(&"guest_corridor", Vector3i(x, 2, 0)):
+		if not _build(&"guest_stairs" if x == -4 else &"guest_corridor", Vector3i(x, 2, 0)):
 			return false
 	if not await advance(10):
 		return false
-	# This walkway follows the upper side of the rooms. Its authoritative Path
-	# projection allows real guests and workers to move between the three levels.
+	# This walkway follows the upper side of the rooms. The final stair segment
+	# gives real guests and the cleaner a legal route to this floor.
 	for x: int in range(-8, 6):
-		if not _build(&"guest_corridor", Vector3i(x, 3, 0)):
+		if not _build(&"guest_stairs" if x == -4 else &"guest_corridor", Vector3i(x, 3, 0)):
 			return false
 	if not await advance(10):
 		return false