bumpHex property
The hex-encoded BRC-74 BUMP that proved the confirmation (ARC's
merklePath, checked against the local header before the command was
sent). WalletProjection stores the merkle proof from it, so the journal,
not the read model alone, holds the proof (bead libspiffy-9ek). Null in
rows journaled before it existed; those replay without a proof.
Implementation
final String? bumpHex;