Bug fixes + archive feature for Destinatäre

- Make Destinatär names clickable in list view (link to detail page)
- Nachweis-Board: auto-create missing VierteljahresNachweis records
  for active Destinatäre when viewing a year (fixes missing Q1 2026)
- Add archive/deactivate toggle for Destinatäre (button on detail page)
  with AuditLog entry and confirmation dialog
- Default Destinatär list to show active only (filter preset to "Aktiv")

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/templates/stiftung/destinataer_list.html

@@ -130,10 +130,10 @@
                                     {% for destinataer in page_obj %}
                                     <tr>
                                         <td>
-                                            <strong>{{ destinataer.vorname|default:"-" }}</strong>
+                                            <a href="{% url 'stiftung:destinataer_detail' pk=destinataer.pk %}" class="text-decoration-none fw-bold">{{ destinataer.vorname|default:"-" }}</a>
                                         </td>
                                         <td>
-                                            <strong>{{ destinataer.nachname }}</strong>
+                                            <a href="{% url 'stiftung:destinataer_detail' pk=destinataer.pk %}" class="text-decoration-none fw-bold">{{ destinataer.nachname }}</a>
                                             {% if destinataer.geburtsdatum %}
                                             <br><small class="text-muted">{{ destinataer.geburtsdatum|date:"d.m.Y" }}</small>
                                             {% endif %}