curl --request POST \
  --url https://core.ravenna.ai/api/ai-brief-schedules/send-now \
  --header 'Content-Type: application/json' \
  --header 'x-ravenna-api-token: <api-key>' \
  --data '{
  "dashboardId": "<string>",
  "slackChannelIds": [
    "<string>"
  ],
  "cadence": "daily",
  "prompt": "<string>",
  "userId": "<string>"
}'

{
  "success": true,
  "workflowId": "<string>",
  "sentToChannels": [
    "<string>"
  ],
  "errors": [
    {
      "channelId": "<string>",
      "error": "<string>"
    }
  ]
}