pub fn resolve_front_door(domain: &str) -> Result<FrontDoorRecord, String>Expand description
Resolve a domain’s QDP front-door record via DoH (Cloudflare), host targets only.
Builds the query name with dns_record_name (_qdp.<domain>), performs a blocking HTTPS
GET https://cloudflare-dns.com/dns-query?name=<name>&type=TXT with the
accept: application/dns-json header (8 s timeout), parses the JSON body, joins the TXT answers
via parse_doh_txt_answers, and decodes them with
FrontDoorRecord::from_dns_txt. All errors are mapped to String.