Bank System with Transfer/Accept and Merge

Requirements Levels 1–2 Implement a conventional account ledger supporting create_account, deposit, withdraw, and atomic transfers between accounts. Level 3 — Two-step transfer A call to transfer(from, to, amount) places the amount on hold rather than immediately crediting the destination. Calling transfer_accept(transfer_id) completes the transfer. While the transfer is pending, the sender’s available balance is lower, whereas the recipient’s balance has not changed. The…