Removes a fax server and everything attached to it: its extension, every user assignment, the email-to-fax list, the number's inbound routing and the stored fax data. The caller-ID number is detached and that change is recorded in the number's history. A fax server a call flow still routes to cannot be deleted until that reference is removed, which comes back as 409. This is irreversible and runs step by step without a transaction, so a failure part-way leaves partial state; an id that does not exist fails as a server error rather than a 404. Requires an API key with the Admin role.