panel-notifications: Account, Server > Settings, Server > Health, help; e2e

The pages of the mockups accepted in 87fa0a4, built from the kit's partials
(written by a Sonnet agent into the working tree, reviewed here):

- Account: "Send me notifications" in the Profile form, saved with the
  profile; an unticked box is off.
- Server > Settings: the instance switch (box 03), and box 04 Notification
  mail with the DKIM and SPF records of the server's own name, drawn with the
  record partial of a domain's DNS page and checked in DNS. Sending rate
  limits are box 02 in the left column. A record that is not in place is
  tagged as a warning, not a failure: notifications are sent without it.
- Server > Health: card 06 Notification mail with the state of each record
  and a link to Settings, beside Configuration (07); part of the polled
  fragment; Re-check DNS forces it too. Overview does not run this check.
- help.go: the Notifications topic and the clauses in Settings and Your
  account, word for word with help.html.

If the server's key cannot be read the pages still render: the DKIM record
is left out and SPF is shown unchecked.

e2e: the administrator gets a mailbox behind the sink and the server's DKIM
record from Settings is published; the level-2 refusal of the next step must
then arrive as a notification from postmaster@mail.e2e.test, signed as that
name with the key Settings shows, and must not be a row of the Outbound log.
The rotation step now waits for Postfix to be running: it follows a step that
restarts the container, and logrotate's `postfix reload` failed in between.

On the test server, for this tree: go vet clean, go test ./... 23 packages
ok, make e2e ok (147 s); the notification reached the sink 28 s after the
refusal.

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

internal/web/view/outbound.go

@@ -178,6 +178,41 @@ func SPFRecord(domain, value string, c DNSCheck) Record {
 	return r
 }
 
+// mailTag is the tag of a record of the server's own name. The records are not
+// needed for notifications to be sent, only for them to arrive, so a record
+// that is missing, wrong or weak is a warning here and never the red a
+// sending domain's would be; published and not checked keep their meaning.
+func mailTag(c DNSCheck) Tag {
+	t := DNSStatusTag(c.Status, len(c.Found) > 0)
+	if tagLevel(t.Status) == LevelFail {
+		t.Status = "warn"
+	}
+	return t
+}
+
+// ServerMailDKIM is the DKIM record of the server's own name, which the panel
+// signs its notifications with: a domain's DKIM record in every other respect.
+func ServerMailDKIM(selector, host, value string, c DNSCheck) Record {
+	r := DKIMRecord(selector, host, value, c)
+	r.Status = mailTag(c)
+	return r
+}
+
+// ServerMailSPF is the SPF record of the server's own name. Without it
+// notifications are still sent, which is said under the value while it is not
+// in place.
+func ServerMailSPF(host, value string, c DNSCheck) Record {
+	r := Record{Name: "SPF", Note: Plain("For the server's own name, not for your domains"),
+		Host: host, Type: "TXT", Value: value}
+	var standing Text
+	if c.Status != "ok" {
+		standing = Plain("Notifications are sent without it, and a receiver may file them as spam.")
+	}
+	applyCheck(&r, c, standing, nil)
+	r.Status = mailTag(c)
+	return r
+}
+
 // DMARCRecordInput is what a DMARC record needs besides its check: where the
 // reports go in words (Source: the address, or "no reports") and the page that changes it,
 // the page of the reports themselves ("" when the panel has none), and whether