curl https://app.okrapdf.com/api/v1/collections \
  -H "Authorization: Bearer okra_YOUR_KEY"

{
  "collections": [
    {
      "id": "col-abc123def456",
      "name": "<string>",
      "doc_count": 123,
      "created_at": "2023-11-07T05:31:56Z",
      "updated_at": "2023-11-07T05:31:56Z",
      "description": "<string>",
      "metadata": {}
    }
  ]
}