025-wire-witness-replay-input

Wire-witness exchanges as remote-exchange and replay evidence (deferred)

Reserves backlog item RUSTEV-013: how a redacted, attempt-bound `wire-witness.exchange/1` record, captured by an independent witness and admitted by its host, may corroborate a Rustev `rustev.remote-exchange/1` record and supply retained response bytes for spec 009's offline mapping check, while preserving requested versus served identity, explicit unknowns, the stricter retention, privacy and cost provenance, and host-owned authorization. Captured traffic that no Rustev attempt produced is never a Rustev decision or replay case. Draft and deferred: depends on wire-witness's exchange record being implemented and on a Rustev remote backend that a witness can observe.