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_approved_free_unique_arrears_ui.gd

@@ -1,4 +1,5 @@
 extends SceneTree
+const FixtureCleanup := preload("res://tests/helpers/ui_audio_fixture_cleanup.gd")
 ## Candidate only, not compiled/executed. Normal construction, staff, save and
 ## load controls are exercised; the sole money fixture is an explicitly labelled
 ## ledger spend at 23:59 using existing valid accounts/category. No tuning edits.
@@ -131,7 +132,11 @@ func run() -> void:
 		var button: Button = main.staff_candidate_buttons.get(&"heroine_anri")
 		expect(button != null and button.is_visible_in_tree() and not button.disabled and button.text == "無料で加入","normal staff pane offers already-approved free Anri despite unrelated debt")
 		if button == null:
-			main.queue_free()
+			var early_cleanup: Dictionary = await FixtureCleanup.free_owner_and_wait(self, main)
+			if not bool(early_cleanup.get(&"passed", false)):
+				push_error("Approved free unique UI ordinary owner cleanup failed: %s" % str(early_cleanup))
+				quit(96)
+				return
 			quit(failures)
 			return
 		var before: Dictionary = runtime.create_snapshot()
@@ -158,7 +163,10 @@ func run() -> void:
 			await process_frame
 			await RenderingServer.frame_post_draw
 			expect(root.get_texture().get_image().save_png(capture) == OK,"rendered named character and unpaid HUD captured")
-	main.queue_free()
-	await process_frame
+	var cleanup: Dictionary = await FixtureCleanup.free_owner_and_wait(self, main)
+	if not bool(cleanup.get(&"passed", false)):
+		push_error("Approved free unique UI ordinary owner cleanup failed: %s" % str(cleanup))
+		quit(96)
+		return
 	print("APPROVED_FREE_UNIQUE_UI phase=%s checks=%d failures=%d" % ["read" if "--read" in OS.get_cmdline_user_args() else "write",checks,failures])
 	quit(failures)