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.

scripts/ui/guest_observation_panel.gd

@@ -66,7 +66,14 @@ func _process(delta: float) -> void:
 		_elapsed = 0
 		refresh()
 
-func refresh() -> void:
+## Clear optional saved presentation while rebuilding the actual loaded roster.
+## Opening or polling the visible observer retains the normal first-row choice.
+func clear_selection() -> void:
+	selected_guest_id = &""
+	_elapsed = 0.0
+	refresh(false)
+
+func refresh(select_first_if_empty: bool = true) -> void:
 	if guests == null or _runtime == null:
 		return
 	var service: Variant = _runtime.get(&"guest_service")
@@ -80,7 +87,7 @@ func refresh() -> void:
 		for id: StringName in _ids:
 			guests.add_item(String(id))
 			guests.set_item_metadata(guests.item_count-1, id)
-	if not _ids.has(selected_guest_id):
+	if not _ids.has(selected_guest_id) and (not selected_guest_id.is_empty() or select_first_if_empty):
 		selected_guest_id = _ids[0] if not _ids.is_empty() else &""
 	guests.disabled = _ids.is_empty()
 	if not _ids.is_empty(): guests.select(_ids.find(selected_guest_id))
@@ -88,7 +95,7 @@ func refresh() -> void:
 	for need: StringName in bars:
 		bars[need].value = report.get(&"needs", {}).get(need, 0)
 	if report.is_empty():
-		details.text = "現在、来客はいません。"
+		details.text = "現在、来客はいません。" if _ids.is_empty() else "来客を選択してください。"
 		priority_label.text = ""
 		decision_label.text = ""
 		return