feat: add session expiry warning

backend/workflows/templates/workflows/base_shell.html

@@ -14,6 +14,16 @@
   {% block extra_head %}{% endblock %}
 </head>
 <body{% block body_attrs %}{% endblock %}>
+  {% if request.user.is_authenticated %}
+  <script>
+    window.WorkdockSessionConfig = {
+      idleTimeoutSeconds: {{ session_idle_timeout_seconds|default:0 }},
+      reauthTimeoutSeconds: {{ session_reauth_timeout_seconds|default:0 }},
+      keepaliveUrl: "/session/keepalive/",
+      loginUrl: "/accounts/login/"
+    };
+  </script>
+  {% endif %}
   {% block pre_shell %}{% endblock %}
   {% if portal_trial_enabled %}
   <div class="app-trial-banner{% if portal_trial_expired %} is-expired{% endif %}">
@@ -93,8 +103,29 @@
       </div>
     </div>
   </div>
+  <div class="confirm-modal" id="app-session-warning-modal" hidden aria-hidden="true">
+    <div class="confirm-backdrop"></div>
+    <div class="confirm-dialog" role="dialog" aria-modal="true" aria-labelledby="app-session-warning-title" aria-describedby="app-session-warning-copy">
+      <div class="confirm-dialog-head">
+        <p class="action-progress-kicker">{% trans "Sitzung" %}</p>
+        <h2 id="app-session-warning-title">{% trans "Ihre Sitzung läuft bald ab" %}</h2>
+      </div>
+      <p class="confirm-message" id="app-session-warning-copy">
+        {% trans "Sie sind weiterhin angemeldet, aber diese Sitzung wird bald ablaufen. Bleiben Sie aktiv, wenn Sie weiterarbeiten möchten." %}
+      </p>
+      <p class="confirm-message" id="app-session-warning-countdown"></p>
+      <div class="confirm-actions">
+        <form method="post" action="{% url 'logout' %}">
+          {% csrf_token %}
+          <button class="btn btn-secondary" type="submit">{% trans "Abmelden" %}</button>
+        </form>
+        <button class="btn btn-primary" type="button" id="app-session-warning-extend">{% trans "Angemeldet bleiben" %}</button>
+      </div>
+    </div>
+  </div>
   <script src="{% static 'workflows/js/confirm_dialog.js' %}?v={{ static_asset_version }}"></script>
   <script src="{% static 'workflows/js/action_progress.js' %}?v={{ static_asset_version }}"></script>
+  <script src="{% static 'workflows/js/session_warning.js' %}?v={{ static_asset_version }}"></script>
   {% block extra_scripts %}{% endblock %}
 </body>
 </html>