Generate Mermaid.js Dashboard from Webhook Data

## IMPORTANT NOTE FOR CLOUD USERS
### Since the cloud version doesn't support environmental variables, please update the following fields:

1. **instance_url**. Change the `{{$env["N8N_PROTOCOL"]}}://{{$env["N8N_HOST"]}}` expression to your cloud instance URL
2. **webhook_path**. Change the `{{$env["N8N_ENDPOINT_WEBHOOK"] || "webhook"}}` simply to the `webhook`. So that the production webhook is called correclty.