Commodity Receipt Token

interface CommodityMetadata {
  commodityType:        string;  // cocoa | coffee | maize | cotton | soybean | palm-oil
  quantityKg:           bigint;
  gradeClassification:  string;  // e.g. "Grade A", "FAQ", "GC1"
  warehouseId:          string;  // Certified warehouse identifier
  warehouseLocation:    string;  // GPS or address of storage
  depositDate:          bigint;  // Unix timestamp
  expiryDate:           bigint;  // Unix timestamp of receipt expiry
  inspectionReportHash: string;  // bytes32 — IPFS hash of inspection report
  valuationUSD:         bigint;  // 18 decimals
  harvestSeason:        string;  // e.g. "2025/2026"
  lastUpdated:          bigint;
}

const now       = BigInt(Math.floor(Date.now() / 1000));
const sixMonths = BigInt(60 * 60 * 24 * 180);

const result = await factory.deployCommodity({
  name:        "Kano Maize Receipt",
  symbol:      "KMR",
  assetId:     "KMR-2025-001",
  countryCode: "NG",
  metadata: {
    commodityType:        "maize",
    quantityKg:           BigInt(5000),
    gradeClassification:  "Grade A",
    warehouseId:          "WH-KANO-001",
    warehouseLocation:    "Dawanau Market, Kano",
    depositDate:          now,
    expiryDate:           now + sixMonths,
    inspectionReportHash: ethers.ZeroHash,
    valuationUSD:         ethers.parseEther("10000"),
    harvestSeason:        "2025/2026",
    lastUpdated:          now,
  },
});

Transfer(address indexed from, address indexed to, uint256 value)
MetadataUpdated(uint256 indexed version, uint256 timestamp)
ReceiptExpired(bytes32 indexed assetId, uint256 timestamp)