Integrate the Blender character, gear and prop library

NpcAvatar
- select one of 8 library character variants by role/seed (with npc_base and the
  procedural rig as fallbacks), keep Rig/Head and the existing bone animation
- tint only skin/cloth/pants/accessory/hair; fixed detail materials keep their
  colour, npc_vest keeps its hi-vis vest, firefighter/guard use dark uniform tints
- attach caps, hoods, helmets, backpacks, SCBA tanks, lanyards and hand items at
  the documented head/back/chest/hand points (primitive fallbacks retained)

WorldBuilder
- prefer assets/models/blender/props/ for the six replacements and the new
  street dressing (street lamp/tree, palms, planters, A-frame, cone, barrier,
  stanchion, podium, handrail, wall lantern, double door, marquee, sedan)
- fit the same colliders/navigation obstacles and keep the placement validator;
  collect library emissives (bulbs, marquee face, wall lanterns, door LED, sedan
  lights) for set_night_mode()
- add a library triangle counter + 60k budget check (current ~27,986); toggle
  prop gallery to the library models; fix the marquee label placement

Tests/smoke
- character selection/gear attach/fixed-material tint tests; library prop load,
  emissive and triangle-budget tests; smoke_props routes a guest around a
  stanchion in open sidewalk (the old bench route is now crowded by trees)
- headless 222/222, Python 68/68, all smokes pass, compare 11 good / 0 bad

Docs: TODO Phase 3.5 moved to DONE, README/architecture/blender-assets/plan
describe the integrated runtime, MEMORY records the integration rules.

src/test/smoke_props.gd

@@ -19,6 +19,7 @@ var failures: Array[String] = []
 var bench: Node3D = null
 var bench_center := Vector3.ZERO
 var bench_body: StaticBody3D = null
+var route_center := Vector3.ZERO
 var guard_start := Vector3.ZERO
 var npc: Node3D = null
 var npc_start := Vector3.ZERO
@@ -46,12 +47,12 @@ func _process(_delta: float) -> bool:
 			_find_bench()
 			if bench == null:
 				return false
-			# Stand a couple of metres in front of the bench and walk into it.
-			var start := bench_center + Vector3(0, 0, 2.2)
+			# Stand on the door side of the bench and walk into it (+z). The
+			# street side is crowded with trees/planters now.
+			var start := bench_center - Vector3(0, 0, 2.0)
 			start.y = 0.1
 			gm.guard.global_position = start
-			# Face the bench (-z): yaw 0 looks down -z, so W walks toward it.
-			gm.guard.rotation.y = 0.0
+			gm.guard.rotation.y = PI
 			guard_start = start
 			Input.action_press("move_forward")
 			step = 1
@@ -59,9 +60,9 @@ func _process(_delta: float) -> bool:
 		1:
 			if step_frame >= GUARD_PUSH_FRAMES:
 				Input.action_release("move_forward")
-				_check(guard_start.z - gm.guard.global_position.z > 0.5,
+				_check(gm.guard.global_position.z - guard_start.z > 0.5,
 					"guard walked toward the bench")
-				_check(gm.guard.global_position.z > bench_center.z + 0.25,
+				_check(gm.guard.global_position.z < bench_center.z - 0.25,
 					"guard stopped at the bench instead of passing through it")
 				_check(not _inside_bench(gm.guard.global_position),
 					"guard is not inside the bench collider")
@@ -71,16 +72,14 @@ func _process(_delta: float) -> bool:
 				step = 2
 				step_frame = 0
 		2:
-			if step_frame % 120 == 0 and npc != null and is_instance_valid(npc):
-				print("npc dbg pos=%s vel=%s arrived=%s wait=%s" % [str(npc.global_position), str(npc.velocity), str(npc.arrived), str(npc.awaiting_interaction)])
 			if npc == null or not is_instance_valid(npc):
 				_stage_npc()
 				return false
 			if _npc_finished():
-				_check(npc.global_position.z < bench_center.z - 0.4,
-					"guest reached the far side of the bench")
-				_check(not _inside_bench(npc.global_position),
-					"guest is not inside the bench collider")
+				_check(npc.global_position.z > route_center.z + 0.35,
+					"guest reached the far side of the stanchion")
+				_check(npc.global_position.distance_to(route_center) > 0.4,
+					"guest is not inside the stanchion collider")
 				_check(npc_start.distance_to(npc.global_position) > 1.0,
 					"guest moved while routing around the prop")
 				_finish()
@@ -112,22 +111,33 @@ func _stage_npc() -> void:
 		step = 0
 		step_frame = 0
 		return
+	var detail := root.find_child("StreetDetail", true, false)
+	route_center = bench_center
+	if detail != null:
+		for child in detail.get_children():
+			if str(child.name).begins_with("Prop_stanchion"):
+				route_center = (child as Node3D).global_position
+				break
 	npc = gm.npcs[0]
-	npc_start = bench_center + Vector3(0, 0.5, 2.5)
+	npc_start = route_center + Vector3(0, 0.5, -2.0)
 	npc.global_position = npc_start
 	npc.velocity = Vector3.ZERO
 	npc.arrived = false
 	npc.awaiting_interaction = false
 	npc.lifetime_s = 999.0
 	npc.reaction_mode = ""
-	# Target well past the bench forces a straight line through it, and stays
-	# beyond the controller's 3 m "arrived" shortcut so the guest must route.
-	npc.target_position = Vector3(bench_center.x, 0.5, bench_center.z - 5.0)
+	if npc.npc != null:
+		# "enter" would send the guest to the door once the path ends; keep this
+		# test focused on routing around the prop.
+		npc.npc.intent = "roam"
+	# A stanchion sits in open sidewalk, so the route is not squeezed by trees
+	# or bins; the target forces a straight line through it.
+	npc.target_position = Vector3(route_center.x, 0.5, route_center.z + 5.5)
 
 func _npc_finished() -> bool:
 	if npc == null or not is_instance_valid(npc):
 		return false
-	return npc.global_position.z < bench_center.z - 0.4 \
+	return npc.global_position.z > route_center.z + 0.35 \
 		or npc.global_position.distance_to(npc.target_position) < 0.9
 
 func _inside_bench(point: Vector3) -> bool: