Build a role registry with an immutable administrator and grants keyed by subject and role. A grant is active exactly when granted and current time is strictly below expiry. Only the administrator can grant/revoke; granting replaces expiry.

Reject zero subject, zero role and non-future expiry. Expose raw grant data separately from active status. Test expiry equality, renewals, revocation, unauthorized calls and cross-user isolation.

Preserve this explicit administrator design. Deliver a standalone Foundry project, meaningful tests, and a README with exact behavior and reproduction commands. Use Solidity 0.8.24 and no fetched test dependencies; builds and tests must work offline with the toolchain installed.

Document assumptions and incomplete checks. Set deployment ON and deploy the tested contract to Sepolia (chain ID 11155111). Deliver the contract address, deployment transaction hash, explorer link and constructor arguments.

Use documented demo parameters and test accounts; keep builds and unit tests reproducible offline. Do not deploy to mainnet or create a token.