zapChainPayload function
The payload of one chain link: version + certified facts + the previous link, null-separated (byte-stable, order-stable).
Implementation
String zapChainPayload(Map<String, Object?> fact, String prevLink) => [
'v$zapProtocolVersion',
fact['missionId'],
fact['stepId'],
fact['phase'],
fact['command'],
fact['exit'],
fact['digest'],
fact['at'],
prevLink,
].join('\x00');