panel: align page URLs, titles, and headings

Settings moves to /settings with a 308 redirect from /account; domains, Status, Users, and user forms get matching browser titles and h1 text; backup page title reflects domain import.

Co-Authored-By: Composer <noreply@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

internal/web/handlers/handlers_backup.go

@@ -45,7 +45,7 @@ func (h *Handlers) renderBackupPage(w http.ResponseWriter, r *http.Request, stat
 // wrong form.
 func (h *Handlers) renderBackupPageWith(w http.ResponseWriter, r *http.Request, status int, importErr, backupErr string) {
 	data := h.pageBase(r)
-	data["Title"] = "SelfPost — backup"
+	data["Title"] = "SelfPost — backup & migration"
 	data["Active"] = "backup"
 	data["ImportErr"] = importErr
 	data["BackupErr"] = backupErr