Mints the inbound webhook URL for this configuration

For one-webhook-per-credential providers (Telegram, Slack Events API, Twilio, Dialog360) where every chat / channel under the same bot shares one URL. The full URL is shown exactly once in the response — read paths only ever expose the template + key prefix. Re-mint via `/webhook:rotate` if the URL is lost; that revokes the previous key, so the operator must re-register the new URL with the provider before traffic resumes. Returns 400 when the integration declares per-binding webhook ownership (the binding-level mint is the right surface for those — activations flow automatically through participant create / update), or when this config already has a key bound (use `/webhook:rotate` to refresh).

curl -X POST "https://api.fruxon.com/v1/tenants/string/integrations/string/configs/497f6eca-6276-4993-bfeb-53cbbbba6f08:generateWebhookUrl"

{
  "webhookUrl": "string",
  "webhookKeyPrefix": "string"
}

{
  "type": "string",
  "title": "string",
  "status": 0,
  "detail": "string",
  "instance": "string",
  "property1": null,
  "property2": null
}

{
  "type": "string",
  "title": "string",
  "status": 0,
  "detail": "string",
  "instance": "string",
  "property1": null,
  "property2": null
}