Upgrade the contract to a new WASM hash. Only callable by admin.
fn upgrade(
env: soroban_sdk::Env,
new_wasm_hash: soroban_sdk::BytesN<32>,
) -> Result<(), TierVerifierError>Initialize the contract with an admin address.
fn initialize(
env: soroban_sdk::Env,
admin: soroban_sdk::Address,
) -> Result<(), TierVerifierError>Store a tier attestation (placeholder for ZK verification).
In the next upgrade, this will perform actual Groth16 verification using Protocol 25 BN254 host functions.
For now, it stores the attestation with a proof hash for later verification.
fn attest_tier(
env: soroban_sdk::Env,
farmer: soroban_sdk::Address,
tier: u32,
commitment: soroban_sdk::BytesN<32>,
proof_hash: soroban_sdk::BytesN<32>,
) -> ResultLookup a farmer's tier attestation.
fn get_attestation(
env: soroban_sdk::Env,
farmer: soroban_sdk::Address,
) -> Option