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/handlers/handlers_account.go

@@ -26,6 +26,7 @@ type accountForm struct {
 	Err      string
 	Username string
 	Email    string
+	Notify   bool
 }
 
 func (h *Handlers) accountUser(w http.ResponseWriter, r *http.Request) (store.User, bool) {
@@ -44,7 +45,7 @@ func (h *Handlers) accountUser(w http.ResponseWriter, r *http.Request) (store.Us
 }
 
 func formOf(u store.User) accountForm {
-	return accountForm{Username: u.Username, Email: u.Email}
+	return accountForm{Username: u.Username, Email: u.Email, Notify: u.Notify}
 }
 
 // HandleAccount shows the Account page.
@@ -58,7 +59,7 @@ func (h *Handlers) HandleAccount(w http.ResponseWriter, r *http.Request) {
 
 func (h *Handlers) renderAccount(w http.ResponseWriter, r *http.Request, status int, u store.User, f accountForm) {
 	page := view.NewAccount(h.shellMeta(r), string(u.Role))
-	page.Username, page.Email = f.Username, f.Email
+	page.Username, page.Email, page.Notify = f.Username, f.Email, f.Notify
 	page.WithResult(accountFlash(r), f.Err)
 	h.view.Render(w, status, "account", page)
 }
@@ -90,6 +91,8 @@ func (h *Handlers) HandleAccountProfile(w http.ResponseWriter, r *http.Request)
 	}
 	f.Username = strings.TrimSpace(r.PostFormValue("username"))
 	f.Email = strings.TrimSpace(r.PostFormValue("email"))
+	// An unticked checkbox is not sent at all: absent is off.
+	f.Notify = r.PostFormValue("notify") != ""
 	if f.Username == "" {
 		f.Username = u.Username
 	}
@@ -112,7 +115,14 @@ func (h *Handlers) HandleAccountProfile(w http.ResponseWriter, r *http.Request)
 		fail(http.StatusInternalServerError, "Could not save the profile. Please check the logs and try again.")
 		return
 	}
-	logf("panel: user %d profile updated (username: %t, e-mail: %t)", u.ID, f.Username != u.Username, f.Email != u.Email)
+	if f.Notify != u.Notify {
+		if err := h.store.SetUserNotify(u.ID, f.Notify); err != nil {
+			logf("panel: account: set notifications of user %d: %v", u.ID, err)
+			fail(http.StatusInternalServerError, "Could not save the profile. Please check the logs and try again.")
+			return
+		}
+	}
+	logf("panel: user %d profile updated (username: %t, e-mail: %t, notifications: %t)", u.ID, f.Username != u.Username, f.Email != u.Email, f.Notify)
 	http.Redirect(w, r, "/account?done=profile", http.StatusSeeOther)
 }