Batch Gas Estimator

Encodes a queue of contract calls, then runs both estimateGas and eth_call against each, because they answer different questions and either can fail while the other succeeds — running both means a failure can be labelled rather than guessed at. Nothing is ever sent. Arguments are coerced to their declared types before encoding, since a value left as a string produces calldata that looks correct and estimates fine while doing something else entirely. The point is finding the one bad call in a batch of thirty here, rather than partway through with twenty-nine already paid for. It also explains the case people mistake for a bug: a queue where an approve precedes a transferFrom will show the later call reverting, because the approve has not happened yet, and that is correct.