Implement StreamNFT, Sablier-style linear ERC-20 streams where each stream is an ERC-721, then have other workers test and review it. Local only: do not deploy. Self-contained (pragma ^0.8.24, no imports): the workspace starts empty and this step may write only src/StreamNFT.sol, so there is no OpenZeppelin or forge-std and none can be added. The file carries a minimal ERC-721 'Stream NFT' / 'SNFT' (balanceOf, ownerOf, approve, getApproved, setApprovalForAll, isApprovedForAll, transferFrom, safeTransferFrom with onERC721Received, ERC-165, tokenURI returning an empty string), an inline reentrancy lock and a transfer helper that accepts no-return tokens.

• createStream(address token, address recipient, uint128 total, uint40 start, uint40 end, bool cancelable) returns streamId (sequential from 1). Requires total > 0, recipient non-zero, start < end and end > block.timestamp (start may be in the past). Pulls exactly total from msg.sender (balance-diff check; fee-on-transfer reverts), records msg.sender as the stream's sender, and mints the NFT to recipient with _mint (no receiver callback).
• streamedAmount(id) at time t: 0 before start, total at or after end, floor(total × (t − start) / (end − start)) in between; after a cancel it is frozen at the value from the cancel block. withdrawable(id) = streamed − withdrawn.
• withdraw(id, address to, uint128 amount) and withdrawMax(id, address to): caller must be the NFT owner, its approved address or an operator; to non-zero; amount ≤ withdrawable. Whoever holds the NFT when withdrawing receives everything streamed and not yet withdrawn, including amounts that streamed before a transfer.
• cancel(id): only the stream's sender, only if cancelable, not cancelled and not fully streamed (else reverts). Refunds total − streamed(now) to the sender immediately, so the sender keeps the rounding remainder, and freezes the stream; the NFT holder can still withdraw the frozen withdrawable.
• burn(id): owner or approved, only when nothing is left to withdraw (withdrawn == streamed and the stream is cancelled or ended).
• getStream(id) returns (sender, token, total, start, end, withdrawn, refunded, cancelable, cancelled); events StreamCreated, Withdrawn, Cancelled plus ERC-721 Transfer. No admin, fee or ETH; effects before token transfers; nonReentrant on createStream, withdraw, withdrawMax and cancel.

Always true: for each stream, withdrawn + refunded + withdrawable ≤ total, with equality once it is cancelled or ended; the contract's balance of each token equals Σ (total − withdrawn − refunded) over that token's streams.