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_first_operating_day.gd

@@ -1,4 +1,5 @@
 extends SceneTree
+const FixtureCleanup := preload("res://tests/helpers/ui_audio_fixture_cleanup.gd")
 
 ## Normal UI commands, default funds, and natural arrivals only. No demo fixture.
 ## Optional THE_TREE_OPENING_CAPTURE=1 renders the new-game and close screens.
@@ -169,7 +170,8 @@ func _run() -> void:
 	await _capture("second-morning")
 	var evidence := {"lodging_sales": lodging_sales, "report": _ledger.get_report(), "staff_count": _runtime.staff_service.get_staff_members().size()}
 	print("FIRST_OPERATING_DAY_REPORT ", JSON.stringify(evidence))
-	var evidence_path := ProjectSettings.globalize_path("res://artifacts/first-operating-day/operating-report.json")
+	var evidence_dir := OS.get_environment("THE_TREE_FIRST_OPERATING_EVIDENCE_DIR")
+	var evidence_path := ProjectSettings.globalize_path("res://artifacts/first-operating-day/operating-report.json" if evidence_dir.is_empty() else evidence_dir.path_join("operating-report.json"))
 	DirAccess.make_dir_recursive_absolute(evidence_path.get_base_dir())
 	var evidence_file := FileAccess.open(evidence_path, FileAccess.WRITE)
 	if evidence_file != null:
@@ -241,5 +243,10 @@ func _expect(condition: bool, message: String) -> void:
 
 
 func _finish() -> void:
+	var _audio_cleanup_final: Dictionary = await FixtureCleanup.free_owner_and_wait(self, _main)
+	if not bool(_audio_cleanup_final.get(&"passed", false)):
+		push_error("Ordinary fixture audio cleanup failed: %s" % str(_audio_cleanup_final))
+		quit(96)
+		return
 	print("First operating day: %d checks, %d failures" % [_checks, _failures])
 	quit(1 if _failures > 0 else 0)