WIP checkpoint: PC2: Build a basic playable test level scene

scripts/smoke_test_test_level.gd

@@ -34,8 +34,10 @@ func _run() -> void:
 		quit(1)
 		return
 
-	# Add to tree so find_child works
-	add_child(level_instance)
+	# Create a temporary root node and add it to the tree so find_child works
+	var root_holder := Node3D.new()
+	add_child(root_holder)
+	root_holder.add_child(level_instance)
 	await process_frame
 
 	# (b) Find the PlayerSpawn marker
@@ -43,6 +45,7 @@ func _run() -> void:
 	if spawn_marker == null:
 		printerr("SMOKE RESULT: FAIL — no Marker3D named 'PlayerSpawn' found in test level")
 		level_instance.queue_free()
+		root_holder.queue_free()
 		quit(1)
 		return
 
@@ -56,6 +59,7 @@ func _run() -> void:
 		printerr("SMOKE RESULT: FAIL — PlayerSpawn y = ", spawn_y,
 				 " is below the required minimum of 1.0 m above ground top (y=0)")
 		level_instance.queue_free()
+		root_holder.queue_free()
 		quit(1)
 		return
 
@@ -66,6 +70,7 @@ func _run() -> void:
 	if ground == null:
 		printerr("SMOKE RESULT: FAIL — no StaticBody3D named 'Ground' found")
 		level_instance.queue_free()
+		root_holder.queue_free()
 		quit(1)
 		return
 
@@ -79,6 +84,7 @@ func _run() -> void:
 		if abs(ground_top - 0.0) > 0.01:
 			printerr("SMOKE RESULT: FAIL — Ground top face at y = ", ground_top, " expected ~0.0")
 			level_instance.queue_free()
+			root_holder.queue_free()
 			quit(1)
 			return
 		print("SMOKE: Ground top face at y = ", ground_top, " — PASS")
@@ -93,12 +99,14 @@ func _run() -> void:
 		if prop_count < 3:
 			printerr("SMOKE RESULT: FAIL — only ", prop_count, " props found, need >= 3")
 			level_instance.queue_free()
+			root_holder.queue_free()
 			quit(1)
 			return
 		print("SMOKE: found ", prop_count, " props — PASS")
 	else:
 		printerr("SMOKE RESULT: FAIL — no 'Props' Node3D found")
 		level_instance.queue_free()
+		root_holder.queue_free()
 		quit(1)
 		return
 
@@ -107,6 +115,7 @@ func _run() -> void:
 	if sun == null:
 		printerr("SMOKE RESULT: FAIL — no DirectionalLight3D named 'Sun' found")
 		level_instance.queue_free()
+		root_holder.queue_free()
 		quit(1)
 		return
 	print("SMOKE: found Sun DirectionalLight3D")
@@ -115,6 +124,7 @@ func _run() -> void:
 	if env == null:
 		printerr("SMOKE RESULT: FAIL — no WorldEnvironment named 'Environment' found")
 		level_instance.queue_free()
+		root_holder.queue_free()
 		quit(1)
 		return
 	print("SMOKE: found WorldEnvironment")
@@ -122,4 +132,5 @@ func _run() -> void:
 	# All checks passed
 	print("SMOKE RESULT: PASS")
 	level_instance.queue_free()
+	root_holder.queue_free()
 	quit(0)