Find similar items across documents and memories

curl --request GET \
  --url https://api.example.com/api/search/similar \
  --header 'Authorization: Bearer <token>'

{
  "results": [
    {
      "source_type": "<string>",
      "score": 123,
      "id": 123,
      "title": "<string>",
      "topic": "<string>",
      "content": "<string>",
      "memory_type": "<string>"
    }
  ]
}