feat(spec)!: retire agent.lifecycle — a conversation phase is a skill, orchestration is Flow, record transitions are the state_machine rule; the XState StateMachineSchema family leaves with it (#21320)

feat(spec)!: retire agent.lifecycle — a conversation phase is a skill, orchestration is Flow, record transitions are the state_machine rule; the XState StateMachineSchema family leaves with it (#21320) #12477