Organization brands overview

Per-brand portfolio overview for one of the user's organizations: AI visibility (value, delta, sparkline), domain rating, open next-steps count, tracked prompts and keywords, and Search/Traffic — plus org KPIs (time saved, articles created, reports sent, active brands). Reads the persisted daily snapshot. Pass organizationId (from list_teams) to target a specific org; omit it when the user belongs to a single org.