milter: the level-2 limit and the client IP list hold for every message

Security fix, outside the inbound antispam feature. Found by its
technical review (Opus, 2026-10-12), reproduced on the test stand
before the fix: over an application's level-2 limit, two MAIL FROM on
one connection were answered 451 and then accepted.

Cause. Postfix introduces a client to a milter once per connection.
The milter library (go-milter 0.4.1, session.go) replaces the milter's
session after any reply that is not "continue" - a refusal, or the
accept that used to end a message. The new session never saw Connect,
so it had no client address, and both checks passed a message without
one: overLimit returned early ("no client IP to key on") and
authIPAllowed did the same. So every message after the first on a
connection, and every MAIL FROM after a refused one, skipped the
level-2 limit and an application's client IP list. In the code since
1.9.0 for the list and longer for the limit.

Fix.
  - build/postfix-config.sh: milter_mail_macros carries {client_addr},
    so the address comes with every MAIL FROM; MailFrom reads it (both
    spellings of IPv6) in the journal milter and the inbound journal
    milter.
  - overLimit no longer asks for a client address: a ceiling is on a
    domain or an application.
  - authIPAllowed refuses an application that has a client IP list when
    no address is known.
  - Body replies "continue" in both milters, which lets the message
    through as "accept" did and keeps the session.

The inbound journal milter had the same cause with a smaller effect:
rows of a connection's later messages had no client address.

In the same file, the checks of INBOUND_ANTISPAM_MILTER and
INBOUND_JOURNAL_MILTER_SOCKET refuse any character outside their set
first: a glob's "*" matched anything after the first characters.

Tests: a session that never saw Connect is judged by the macro, a
listed and an unlisted address, no address, not an address; the limit
with no client address; the inbound milter answers only "continue".
test/e2e sends two MAIL FROM on one connection over the limit and
wants both refused.

Checked on the test server: e2e red before the fix on exactly that
check, green after; go vet ./... ok, go test ./... ok (22 packages).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/milter/ratelimit.go

@@ -26,10 +26,9 @@ import (
 // reaches the send log (or is abandoned) — see inflight for why the stored
 // count alone is not enough.
 func (s *session) overLimit() bool {
-	if s.clientIP == "" {
-		return false // no client IP to key on; level-2 does not apply
-	}
-
+	// A ceiling is on a domain or an application, whatever address the mail
+	// comes from, so the client address is not asked for here. It used to be,
+	// and a message that arrived without one was let through uncounted.
 	if s.login != "" {
 		rl, ok, err := s.rec.RateLimit(store.RateLimitScopeApp, s.login)
 		if err != nil {