Carbon Credit Token

interface CarbonCreditMetadata {
  creditType:          string;  // REDD+ | VCS | Gold Standard | GS4GG | CDM
  verificationBodyRef: string;  // e.g. "VERRA-001", "GOLDSTANDARD-042"
  vintageYear:         bigint;  // Year credits were generated
  quantityCO2e:        bigint;  // 18 decimals — 1e18 = 1 tCO2e
  projectLocation:     string;  // e.g. "Congo Basin, DRC"
  projectType:         string;  // Forestry | Agriculture | Energy | Waste
  verificationDocHash: string;  // bytes32 — IPFS hash
  lastUpdated:         bigint;
}

const result = await factory.deployCarbonCredit({
  name:        "Congo Basin REDD+ Credits",
  symbol:      "CBREDD",
  assetId:     "REDD-DRC-2025-001",
  countryCode: "CD",
  metadata: {
    creditType:          "REDD+",
    verificationBodyRef: "VERRA-001",
    vintageYear:         BigInt(2025),
    quantityCO2e:        ethers.parseEther("10000"),  // 10,000 tCO2e
    projectLocation:     "Congo Basin, Democratic Republic of Congo",
    projectType:         "Forestry",
    verificationDocHash: ethers.ZeroHash,
    lastUpdated:         BigInt(Math.floor(Date.now() / 1000)),
  },
});

const token = adapter.carbonCreditToken(tokenAddress);

await token.retire(
  ethers.parseEther("100"),    // 100 tCO2e
  "Acme Corp — 2025 scope 1", // beneficiary label
  "Annual carbon offset programme"
);

Transfer(address indexed from, address indexed to, uint256 value)
MetadataUpdated(uint256 indexed version, uint256 timestamp)
CreditsRetired(
  address indexed retiredBy,
  uint256 amount,
  string beneficiary,
  uint256 retirementIndex,
  uint256 timestamp
)