curl -X GET "https://api.adrelay.dev/v1/connections" \
  -H "X-API-Key: $ADRELAY_API_KEY"

{
  "connections": [
    {
      "id": "conn_abc123",
      "platform": "google_ads",
      "status": "ACTIVE",
      "label": "Main Google Account",
      "remote_account_id": "123-456-7890",
      "created_at": "2026-03-01T12:00:00Z",
      "last_synced_at": "2026-03-21T08:00:00Z"
    },
    {
      "id": "conn_def456",
      "platform": "meta_ads",
      "status": "ACTIVE",
      "label": null,
      "remote_account_id": "act_987654321",
      "created_at": "2026-03-05T10:00:00Z",
      "last_synced_at": "2026-03-21T08:00:00Z"
    }
  ]
}