curl --request GET \
  --url https://api.adapter.com/v1/knowledge/entity-stats

{
  "user_id": "<string>",
  "total_entities": 123,
  "total_evidence_processed": 123,
  "entities_by_type": [
    {
      "entity_type": "<string>",
      "count": 123,
      "domain_routed_count": 123,
      "llm_routed_count": 123,
      "avg_confidence": 123,
      "earliest_entity_timestamp": "<string>",
      "latest_entity_timestamp": "<string>"
    }
  ],
  "overall_earliest_timestamp": "<string>",
  "overall_latest_timestamp": "<string>"
}