OptionalDisplayThe participant's display name as Meet reports it.
OptionalIsWhether this participant is the bridge's own bot (so the driver can exclude it from diarization addressing).
The Meet participant id (stable for the participant's presence in the conference).
The participant's meeting role.
One Google Meet participant as the seam reports it. Platform-native and minimal — the driver maps this onto
BridgeParticipantInfo/BridgeMeetingParticipant.