Welcome
@Serializable
@SerialName(value = "welcome")
Sent by the host to confirm admission.
Also broadcast to all other already-admitted members so they can update their rosters.
assignedPeerId — the new member's us.tractat.kuilt.core.PeerId value. identity — the identity the new member declared in their Hello. roomId — the host's stable room identifier; null in bootstrap welcomes for existing members. Joiners use this to mint their us.tractat.kuilt.session.partition.ResumeToken.