Generate a Korean transaction statement (거래명세서) as XLSX

Example request

{
  "from": {
    "name": "다고툴즈",
    "business_number": "280-30-01413"
  },
  "to": {
    "name": "(주)예시상사"
  },
  "date": "2026-10-12",
  "items": [
    {
      "name": "A4 용지",
      "spec": "80g 500매",
      "qty": 10,
      "unit_price": 5500
    }
  ],
  "vat": "included"
}