An admin/analyst's pet counted every user's sessions (live, waiting, errors)
because their WebSocket carries everyone's. Server mode now marks their
session/agent/event frames `mine: true|false` (scope.broadcastAudience owners,
worked out once per broadcast), and GET /api/sessions?mine=1 lists only the
caller's own sessions (ownSessionWhere). The pet seeds from mine=1 and skips
frames marked mine: false. Developers and local mode are unchanged.
