Session Policy
data class SessionPolicy(val maxAuthenticatedSessions: Int = SessionAuthority.DEFAULT_MAX_AUTHENTICATED_SESSIONS)
Session-count policy. Every authenticated session is equivalent (no role ladder -- see SessionAuthority); maxAuthenticatedSessions is the only cap that still applies, mirroring what used to be PairingSessionPolicy.maxAuthenticatedSessions before the CONTROL/ADMIN-specific caps were removed along with the role ladder itself.