v0.5.1

Added

• A malformed-request WalletInput kind ({ kind, text, cause }) and a
  malformedRequest handler slot in WalletInputHandlers. It sits after
  wallet-api-message and before credentials: a wallet API message recognized
  by shape but refused at the parse boundary lands there, with the refusal as
  cause. Without a malformedRequest handler, handleWalletInput throws
  UnhandledWalletInputError with kind malformed-request. The kind is
  additive for callers that switch on kind with a default branch. Callers with
  an exhaustive switch gain a case.

Fixed

• classifyWalletInput no longer throws on a VPR naming DIDAuthentication
  more than once. It classifies it as malformed-request (WR-2).