List campaigns

curl --request GET \
  --url https://app.autocalls.ai/api/user/campaigns \
  --header 'Authorization: Bearer <token>'

{
  "campaigns": [
    {
      "id": "<string>",
      "name": "<string>",
      "created_at": "<string>",
      "updated_at": "<string>",
      "status": "<string>"
    }
  ]
}