Headline knowledge-gap KPIs for the org over a date window

curl --request GET \
  --url https://api-sandbox.featherhq.com/v1/knowledge-gaps/summary \
  --header 'x-api-key: <api-key>'

{
  "total_sessions_analyzed": 123,
  "knowledge_gap_rate": 123,
  "total_gap_events": 123,
  "active_gap_clusters": 123,
  "critical_gap_clusters": 123,
  "top_gap_types": [
    {
      "bucket": "<string>",
      "count": 123
    }
  ],
  "top_product_areas": [
    {
      "bucket": "<string>",
      "count": 123
    }
  ],
  "average_impact_score": 123,
  "fixed_clusters_count": 123,
  "reopened_clusters_count": 123
}