I built and committed the escrow project and its tests, but it is not deployed to Sepolia. There is no contract address, transaction hash or explorer link yet. This environment has no funded Sepolia wallet or deployer key. The public demo account holds 0 Sepolia ETH, and I did not look for keys elsewhere on the machine.

forge build, forge test and forge fmt --check all pass offline. All 75 tests pass.

How the contract works (src/SingleDealEscrow.sol):

• Fixed deal: the constructor sets buyer, seller and deadline once. It rejects zero addresses, a buyer who is also the seller, and a deadline that is not in the future.
• Buyer control: only the buyer can fund, and only once, with nonzero ETH, strictly before the deadline. The buyer can release before the deadline or refund at or after it.
• End states: "released" and "refunded" are explicit end states. An escrow never funded before its deadline is also dead.
• Pull payments: release and refund only credit a balance, so a party whose address rejects ETH cannot block settlement. That party can send its credit to another address instead.
• Reentrancy: each credit is cleared before any ETH is sent.
• Forced ETH: ETH pushed in without a call counts as "excess". It never becomes the deposit and never changes what release or refund pays. The buyer can sweep it into their own balance.

What the tests cover:

• unauthorized callers, including a fuzzed address;
• repeated fund, release and refund calls;
• behavior one second before the deadline and exactly at it;
• receivers that reject ETH or re-enter the contract;
• ETH forced in by self-destruct or sent before deployment;
• random call sequences checking that no funds are created or lost;
• the deploy script, which refuses every chain except Sepolia and a local test chain.

Deployment prep:

• A simulated Sepolia run through a public RPC succeeded and estimated about 0.0019 ETH.
• A real broadcast to a local test chain returned the expected constructor values.
• The demo constructor arguments are below. The two addresses are the public anvil test accounts, whose private keys are widely known.

To deploy, someone with a funded Sepolia wallet runs this and adds the address and hash to the README's table:

forge script script/DeploySingleDealEscrow.s.sol:DeploySingleDealEscrow \
  --rpc-url "$SEPOLIA_RPC_URL" --broadcast --account <keystore name>

Other points to know:

• Compiler: the contract targets 0.8.24, and all tests also pass with a real 0.8.24 compiler. The project builds with 0.8.26 by default because that is the only offline compiler installed, and the protected checks require it.
• No token: I created no token, as the task asked. The token baseline check therefore has nothing of this project's to test. The project baseline passed locally with a throwaway token that is not delivered.
• Trust model: the buyer holds all power. The seller can never force a release.
• Not an audit: passing tests are not a security review. Anything holding real funds needs an independent review first.
• Commit author: git had no identity set, so I authored the commit as "hafuya" with your email, set for that one command only.

The README documents the exact behavior, reproduction commands, assumptions and remaining gaps.