Save The Tree implementation and acceptance work in progress

Preserve production code, regression fixtures, audio assets and provenance, test infrastructure, and the original-completion plan and progress ledger. Final game and Windows acceptance remain pending; excluded local artifacts and native experiments are not part of this snapshot.

tests/ui/test_elevator_management.gd

@@ -1,5 +1,7 @@
 extends SceneTree
 
+const AudioTeardown := preload("res://tests/helpers/ui_audio_teardown.gd")
+
 var _checks := 0
 var _failures := 0
 var _main: Control
@@ -35,7 +37,7 @@ func _run() -> void:
 	var report: Dictionary = _runtime.elevators.get_report()
 	_expect(report[&"shafts"].size() == 1, "completed paid lift registers one real car")
 	if report[&"shafts"].size() != 1:
-		_finish()
+		await _finish()
 		return
 	_shaft_id = report[&"shafts"][0][&"shaft_id"]
 	_module_id = report[&"shafts"][0][&"module_ids"][0]
@@ -81,7 +83,7 @@ func _run() -> void:
 		var image_value := root.get_texture().get_image()
 		DirAccess.make_dir_recursive_absolute(ProjectSettings.globalize_path("res://artifacts/transport"))
 		image_value.save_png("res://artifacts/transport/elevator-inspector.png")
-	_finish()
+	await _finish()
 
 func _shaft() -> Dictionary:
 	for row: Dictionary in _runtime.elevators.get_report()[&"shafts"]:
@@ -91,6 +93,8 @@ func _shaft() -> Dictionary:
 
 func _finish() -> void:
 	_clock.set_paused(true)
+	var teardown: Dictionary = await AudioTeardown.free_owner_and_wait(self, _main)
+	_expect(bool(teardown.get(&"passed", false)) and not bool(teardown.get(&"deadline_reached", true)), "owned audio references release before bounded teardown deadline with whole Runtime unchanged")
 	print("Elevator management UI: %d checks, %d failures" % [_checks, _failures])
 	quit(_failures)