feat: add Notifications menu item to Platform Monitoring section

Add sidebar navigation link to /admin/notifications page.

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/templates/admin/partials/sidebar.html

@@ -122,8 +122,7 @@
         {{ menu_item('imports', '/admin/imports', 'cube', 'Import Jobs') }}
         {{ menu_item('background-tasks', '/admin/background-tasks', 'collection', 'Background Tasks') }}
         {{ menu_item('logs', '/admin/logs', 'document-text', 'Application Logs') }}
-        {# TODO: Implement notifications settings page #}
-        {# {{ menu_item('notifications-settings', '/admin/notifications-settings', 'bell', 'Notifications') }} #}
+        {{ menu_item('notifications', '/admin/notifications', 'bell', 'Notifications') }}
     {% endcall %}
 
     <!-- Platform Settings Section -->