Returns top contacts ranked by contact_points_balance for the authenticated account, optionally filtered by tag UUIDs. Each result is identified by contact_uuid. The list is bounded by limit (default 25, max 100). Tag filtering accepts UUIDs only -- the legacy CI contract that filtered by tag NAMES (with_tags=name1,name2) is no longer supported on the new REST surface; unknown tag UUIDs return 422 with a canonical envelope. Both with_tag_uuids and without_tag_uuids accept either a comma-separated string OR a JSON array.