List roles

curl --request GET \
  --url https://agentgateway-admin.dev.neuraltrust.ai/v1/gateways/{gateway_id}/roles \
  --header 'Authorization: <api-key>'

{
  "items": [
    {
      "created_at": "<string>",
      "gateway_id": "<string>",
      "id": "<string>",
      "idp_mapping": [
        123
      ],
      "mcp_policies": {
        "toolkit": [
          {
            "expose_as": "<string>",
            "prompt": "<string>",
            "registry_id": "<string>",
            "resource": "<string>",
            "tool": "<string>"
          }
        ]
      },
      "model_policies": [
        {
          "allowed": [
            "<string>"
          ],
          "default": "<string>",
          "registry_id": "<string>"
        }
      ],
      "name": "<string>",
      "registry_ids": [
        "<string>"
      ],
      "updated_at": "<string>"
    }
  ],
  "page": 123,
  "size": 123,
  "total": 123
}