GET /api/activity/reports/security-event-context/

Return the activity context surrounding a single security event (event) — the enclosing trace's references and security events, plus other same-agent security events within a few minutes (any trace), each carrying its full detail — for the before/after timeline on the event detail. Resolution is by event id within the organization, with no date-range / group filter, so a shared link always resolves the anchor within the recipient's permission scope. Restricted to organization admins/managers or activity & security report viewers, and gated by the activity-tracking flag.