Port 465 expects implicit TLS (SMTP_SSL) from the first byte. The email
adapter always used SMTP() + starttls(), which is correct for port 587
but hangs/fails on port 465 providers (e.g., Swiss ISPs).
Additionally, when the SMTP host has AAAA DNS records but IPv6 is
unreachable, socket.create_connection() tries IPv6 first and hangs
until timeout. Add an IPv4 fallback via AF_INET socket.
Extract _connect_smtp() helper to consolidate the 4 duplicate SMTP
connection sites into a single method with correct protocol selection
and IPv6 fallback logic.
04d4471d79