fix(firms): retry over IPv4 when every address fails to connect

Node's network-family auto-selection gives each resolved address a short
attempt timeout. On hosts where IPv6 is unreachable, a slow IPv4 handshake
is abandoned for the IPv6 address, which fails at once, and the request
reports only `fetch failed`. Retry such failures once with a single IPv4
connection within the same deadline, and log the per-address connection
errors (never the keyed URL). Node 26 wraps the AggregateError one level
deeper, so both shapes are recognised.

Fixes #68

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+- FIRMS fire data loads on hosts where IPv6 is unreachable and IPv4 is slow to
+  connect: a request whose every address fails to connect retries once over
+  IPv4, and FIRMS warnings name the underlying connection errors instead of
+  only `fetch failed`.
+
 - Treat explicitly current, complete empty vessel coverage as a successful update,
   clearing obsolete contacts while retaining stale or incomplete snapshots.