wip(14-email-templates): CRUD szablonów e-mail z Quill.js + system zmiennych

APPLY in progress — checkpoint human-verify awaiting re-test po namespace fixes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

resources/views/layouts/app.php

@@ -98,6 +98,9 @@
             <a class="sidebar__sublink<?= $currentMenu === 'settings' && $currentSettings === 'email-mailboxes' ? ' is-active' : '' ?>" href="/settings/email-mailboxes">
               Skrzynki pocztowe
             </a>
+            <a class="sidebar__sublink<?= $currentMenu === 'settings' && $currentSettings === 'email-templates' ? ' is-active' : '' ?>" href="/settings/email-templates">
+              Szablony e-mail
+            </a>
           </div>
         </details>
       </nav>