- Atlas: add requireTeam() at router level; replace client ?teams= param
parsing with req.teamScope in /metrics, /status, and /sync endpoints
- Archive: add requireTeam() at router level; replace client ?teams= param
parsing with req.teamScope in GET / and GET /stats endpoints
- db-schema.sql: add impersonate_user_id column to sessions table reference
The frontend still sends ?teams= as a query param to these endpoints
(harmless no-op since backend ignores it). Frontend cleanup deferred
to avoid churn in the 7000-line ReportingPage component.