P05-02: 全費目と資金区分：表金・裏金、維持費未払い、仕入れ、人件費、元本、利息、税の帳簿への接続（原 P05-02 の完了の条件）

tests/business/test_required_kitchen.gd

@@ -300,6 +300,28 @@ func _approved_runtime_migrations(expected: Dictionary, reader: Dictionary) -> D
 		old[&"elevators"] = raised
 		fields.append("elevators_v1_to_v2")
 		proof["elevators"] = {"only_version_changed": same_otherwise}
+	# P05-02 A12: a save from before the funds were split gains the five empty fund
+	# accounts on load; every other economy field stays byte-identical.
+	var has_back_cash := func(economy: Variant) -> bool:
+		if not economy is Dictionary:
+			return false
+		for account: Variant in (economy as Dictionary).get(&"accounts", []):
+			if account is Dictionary and String((account as Dictionary).get(&"account_id", "")) == "BACK_CASH":
+				return true
+		return false
+	if not has_back_cash.call(old.get(&"economy")) and has_back_cash.call(now.get(&"economy")):
+		var added := {"BACK_CASH": false, "LOAN_INTEREST_EXPENSE": false, "LOAN_INTEREST_PAYABLE": true, "RANK_TAX_EXPENSE": false, "RANK_TAX_PAYABLE": true}
+		var economy: Dictionary = (old[&"economy"] as Dictionary).duplicate(true)
+		var accounts: Array = (economy[&"accounts"] as Array).duplicate(true)
+		for account_id: String in added:
+			accounts.append({&"account_id": account_id, &"allow_negative": added[account_id], &"system": false})
+		accounts.sort_custom(func(left: Dictionary, right: Dictionary) -> bool: return String(left[&"account_id"]) < String(right[&"account_id"]))
+		economy[&"accounts"] = accounts
+		var only_accounts_added: bool = var_to_bytes(economy) == var_to_bytes(now[&"economy"])
+		ok = ok and only_accounts_added
+		old[&"economy"] = economy
+		fields.append("economy_A12_empty_fund_accounts")
+		proof["economy_A12"] = {"added_accounts": added.keys(), "only_accounts_added": only_accounts_added}
 	if not fields.is_empty():
 		# Saves keep the Runtime's own key order, so the mapped tree follows it.
 		ok = ok and old.size() == now.size()