Get dashboard call observability bundle

Bound to the authenticated workspace call before owner checks. Includes a safe appointment projection (id, UTC interval, timezone and state: submitting, booked, unavailable, unconfirmed or not_created); credentials, provider identities and reconciliation leases are excluded. closing_evidence contains bounded post-call close-owner receipts and an independent canonical ending. A tool result, accepted request, owner commit or provider close command is not proof of disconnection. Missing historical receipts stay unavailable. The existing paginated transcript API remains a stream of turns and uncaptioned caller moments; closing/tool receipts are obtained here. No live receipt transport is provided.