How the Go program (modules/mailu/cmd/automx) answers differently from the automx2 2021.6 answers captured here
(issue 1631, ADR 0480 clause 9). automx_test.go answers every .request and compares with the capture; this is the
whole list of where the two differ.

1. The IMAP server's name (the one correction clause 9 allows). automx2 answered <hostname /> for the incoming
   server because its setup script read AMX_IMAP_SERVER, which mailu's environment does not set (it sets
   AMX_IMAP_ADDRESS). The program names it from AMX_IMAP_ADDRESS (and the port from AMX_IMAP_PORT).
   Fixtures 01, 02 and 03 each have a <stem>.corrected.body: the capture with <hostname /> replaced by
   <hostname>mail.novox.be</hostname> and nothing else (a test checks that). Their Content-Length is that file's
   size, 634, not the captured 612.

2. The Server header. The capture has "Server: Werkzeug/3.1.9 Python/3.9.5". The program sends no Server header, and
   Date, which the captured .headers leave out, is sent as net/http sends it.

Not changed, though issue 1691 calls them faults; they are kept as captured because clause 9 allows only the first
correction, and their cause is not known from the capture:
  - Outlook's POST for a served domain (fixture 08) answers 500.
  - Apple's /mobileconfig/ for a served domain (fixture 15) answers 400 with no profile.
  Whether automx2 failed there because of the empty IMAP name is a guess; it can be tested only against the
  running program after the delivery. Issue 1691 stays open for them.

Assumptions the fixtures do not settle (answers to requests nobody captured): a domain is compared in lower case;
an address without "@" is an unknown domain (204); HEAD is answered as GET and OPTIONS with the Allow header and
no body; the redirect of /mobileconfig takes its scheme and host from X-Forwarded-Proto and X-Forwarded-Host when
present (the route sends the client's, as fixture 14's Location shows) and from the request otherwise.