Participant

def to_dict(self) -> dict[str, Any]:
    return {
        "agent_id": self.agent_id,
        "role": self.role.value,
        "order": self.order,
        "joined_at": self.joined_at,
    }

@classmethod
def from_dict(cls, data: dict[str, Any]) -> "Participant":
    payload = dict(data)
    role = payload.get("role")
    if isinstance(role, str):
        payload["role"] = ParticipantRole(role)
    return cls(**payload)