An activity message as an app supplies it, for example in a saved
transcript passed to setMessages. The id is required. links is
optional and, when present, only its subagentRunId is kept: the other
links are recomputed from the activity's position in the list.
API
export type ActivityMessageInput = Prettify <
Omit <
ActivityMessage ,
"links"
> & {
links?: ActivityLinks ;
}
>;