List signals

[
  {
    "id": 50213,
    "signalId": "acme_high_value_customers",
    "customerId": 1001,
    "adcpAgentId": null,
    "name": "Acme - High-Value Customers",
    "description": "Top 10% LTV customers, refreshed weekly",
    "keyType": ["rampid", "uid2"],
    "regions": ["NORAM", "EMEA"],
    "metadata": null,
    "isLive": false,
    "archivedAt": null,
    "createdBy": "agent@acme.example",
    "updatedBy": null,
    "createdAt": "2026-06-06T12:00:00Z",
    "updatedAt": "2026-06-06T12:00:00Z",
    "access": [
      {
        "id": 9001,
        "signalId": 50213,
        "advertiserId": 88421,
        "visibility": "PROPRIETARY",
        "price": null,
        "archivedAt": null,
        "createdAt": "2026-06-06T12:00:00Z",
        "updatedAt": "2026-06-06T12:00:00Z"
      }
    ]
  }
]