Single lifecycle entry surfaced by the in-process
GraphRunStream.lifecycle projection. Combines the CDDL
LifecycleData payload with the namespace it applies to so
consumers can filter or correlate without dipping into raw
ProtocolEvents.
interface LifecycleEntryResolves to an error message string if ToolCallStream.status is
"error", otherwise undefined.
Wall-clock timestamp (milliseconds) of the emission.