Revert Reason Decoder

A mined failure keeps no reason, so this replays the exact call against the block it failed in to recover the revert data. Decodes require() strings, Solidity panic codes with what each one actually means, and custom errors from an ABI you supply — distinguishing a deliberate rejection from a genuine bug, which the raw bytes alone will not tell you. Replaying a failed call needs an RPC that serves state at the failing block. Some public endpoints strip revert data entirely, and the app says so rather than reporting the transaction as unexplained. A custom error with no ABI shows its four-byte selector so it can be identified elsewhere.