dev.malpercio.cards.witness

An appview's signed observation of a card changing hands, written into the appview's own repo. Triggered by a dev.malpercio.cards.item appearing on the firehose. Accepted witnesses form a prev-linked chain per give; exactly one accepted witness exists per (give, hop). Rejected witnesses explain why a claimant's item is not recognized. The chain is durable against player-side deletions and auditable by replaying the firehose.