Variable refundPaymentSchema`Const`

refundPaymentSchema: ZodObject<
    {
        amount: ZodOptional<ZodCoercedNumber<unknown>>;
        checkoutId: ZodString;
        reason: ZodOptional<ZodString>;
    },
    $strict,
> = ...

退款入参（旧 RefundPaymentDto·amount 省略即全额退）。