Network lookups

Each of these calls a small server route — the browser never talks to the upstream service directly.

• DNS lookupA, AAAA, MX, TXT, NS, CNAME
• WHOIS / RDAPdomain and IP registration data
• ASN lookupIP to autonomous system, or AS details
• Port checkercommon ports, rate-limited
• GeoIP lookupapproximate country, city, coordinates