List sessions

curl --request GET \
  --url https://api.traversal.com/v1/sessions \
  --header 'Authorization: Bearer <token>'

{
  "sessions": [
    {
      "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
      "input": "Our checkout service started returning 500 errors at 2024-03-15T14:30:00Z. Error rate jumped from 0.1% to 15%.",
      "created_at": "2024-03-15T14:35:00Z",
      "title": "Elevated error rate in checkout service",
      "updated_at": "2024-03-15T14:38:12Z",
      "messages": [
        {
          "id": "msg-001-uuid",
          "markdown_content": "## Investigation Summary\n\nI investigated the elevated error rate...",
          "created_at": "2024-03-15T14:38:12Z"
        }
      ]
    }
  ],
  "count": 123,
  "total": 123,
  "prev": 123,
  "next": 123
}