Parse TLS details (version, cipher, bits, cert verification) from the
Postfix Received header parenthetical and expose them per hop, rendered
as a per-hop badge in the Email Path card.
Add an x-tls Authentication-Results result: parse it when present, and
otherwise synthesize it from the inbound hop's TLS info. A negative
result (unencrypted inbound connection) applies a -10 authentication
score penalty and is shown in the Authentication card. Enable the TLS
handler in authentication_milter.
Closes: #40
