Verify CLI reference

Subcommand	Purpose
confium verify composite	Verify a composite (COSE) signature
confium verify inclusion	Verify a transparency inclusion proof
confium verify cert-chain	Verify a certificate chain
confium verify signatif	Full SIGNATIF pipeline over a trusted artifact

Exit code 2 means “verification ran, acceptance policy rejected” — distinct from 1 (bad input) in scripts. Product docs: https://www.confium.org/verify/