Create Population

{
  "data": {
    "id": "0c93fab1‑…",
    "avg_mean_absolute_error": 0.1472,
    "avg_mean_squared_error": 0.2311,
    "avg_normalised_kullback_leibler_divergence": 0.0063,
    "created_at": "2025-06-23T15:38:01Z",
    "description": "Baseline LLM population for mobility survey",
    "name": "Urban mobility survey",
    "public": true,
    "question_count": 42,
    "reality_target": "US commuters",
    "simulacrum_count": 5,
    "simulation_engine": "gpt-4o",
    "status": "TESTING",
    "test_finished_at": "2023-11-07T05:31:56Z",
    "test_started_at": "2023-11-07T05:31:56Z",
    "upload_filename": "seed_data.csv"
  },
  "errors": [
    {
      "code": "<string>",
      "message": "<string>"
    }
  ]
}