Get all completed expert responses for a domain

{
  "responses": [
    {
      "requestId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "briefId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "briefTitle": "How to choose running shoes",
      "invitationId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "expertEmail": "jane.doe@acme.com",
      "completedAt": "2026-05-25T10:30:00.000Z",
      "questions": [
        {
          "questionId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
          "sectionTitle": "Finding your fit",
          "question": "What factors matter most when choosing running shoes?",
          "answer": "Gait and cushioning are the two biggest factors.",
          "answeredAt": "2026-05-25T10:30:00.000Z"
        }
      ]
    }
  ]
}