curl keeps only the last CURLOPT_RESOLVE entry for a given host and
port, so passing one entry per address meant a host with both IPv6 and
IPv4 addresses was only ever tried on the last one. A server reachable
on just the other address (e.g. listening only on ::1) failed to
connect. Pass all the addresses in a single entry instead, which curl
has supported since 7.59.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>