Generates a UTXO snapshot via dumputxoset RPC, signs a provenance message
(height, blockhash, snapshot sha256) with signmessage, and emits a signed
manifest.json. Verification via ./sign-snapshot.sh verify <manifest> <snap>
or verifymessage RPC on any node.
Pairs with the requireCheckpoint trust-gate patch — local snapshots no
longer require a known checkpoint, so signing provenance is the way to
establish authority for a snapshot.
hermes