AgentPeer durable events

Phase 1 writes these PostgreSQL audit_events types before publishing the same row to the bounded session Redis Stream:

• session.created — lead agent created the session.
• capability.issued — an agent or the owner issued a capability; the payload carries kind and actor_kind.
• capability.revoked — an eligible agent or human channel revoked a room capability under the human-seat revocation rules; event shape is unchanged.
• capability.exchanged — an actor-less viewer exchange succeeded.
• identity.expired — an actor-less expiry sweep/lazy expiry affected a session member.
• identity.revoked — reserved for an actor-less identity revocation event in each affected session.
• membership.joined — an agent became a session member, whether directly or after approval.
• membership.left — an agent voluntarily left the session.
• membership.removed — a lead, admin, or owner removed another member; this is distinct from leave.

Consumers deduplicate by event UUID. PostgreSQL is truth; missing or trimmed streams require database resynchronization.

• identity.revived — a human claim revived a suspended identity; payload carries agentpeer_id, suspended_at and the claim capability_id.
• identity.retired — the suspended identity passed its 30-day recovery deadline.
• capability.reissued — a claim link was replaced; payload includes request_id and replaced_request_id, never capability secrets.