Enhanced quarterly confirmation system with approval workflow and export improvements

Features added:
- ✅ Fixed quarterly confirmation approval system with URL pattern
- ✅ Added re-approval and status reset functionality for quarterly confirmations
- ✅ Synchronized quarterly approval status with support payment system
- ✅ Enhanced Destinataer export with missing fields (anrede, titel, mobil)
- ✅ Added quarterly confirmation data and documents to export system
- ✅ Fixed address field display issues in destinataer template
- ✅ Added quarterly statistics dashboard to support payment lists
- ✅ Implemented duplicate support payment prevention and cleanup
- ✅ Added visual indicators for quarterly-linked support payments

Technical improvements:
- Enhanced create_quarterly_support_payment() with duplicate detection
- Added get_related_support_payment() method to VierteljahresNachweis model
- Improved quarterly confirmation workflow with proper status transitions
- Added computed address property to Destinataer model
- Fixed template field mismatches (anrede, titel, mobil vs strasse, plz, ort)
- Enhanced backup system with operation tracking and cancellation

Workflow enhancements:
- Quarterly confirmations now properly sync with support payments
- Single support payment per destinataer per quarter (no duplicates)
- Approval button works for both eingereicht and geprueft status
- Reset functionality allows workflow restart
- Export includes complete quarterly data with uploaded documents

app/templates/stiftung/unterstuetzungen_list.html

@@ -212,6 +212,47 @@
   </div>
 </div>
 
+<!-- Quarterly Confirmation Statistics -->
+<div class="row mb-4">
+  <div class="col-12">
+    <div class="card">
+      <div class="card-header bg-light">
+        <h6 class="card-title mb-0">
+          <i class="fas fa-chart-pie me-2"></i>
+          Vierteljahresnachweis Status Übersicht
+        </h6>
+      </div>
+      <div class="card-body py-2">
+        <div class="row text-center g-0">
+          <div class="col-lg-2 col-md-3 col-4 mb-2">
+            <div class="px-2">
+              <div class="h5 fw-bold text-primary mb-0">{{ total_quarterly }}</div>
+              <small class="text-muted">Gesamt</small>
+            </div>
+          </div>
+          {% for status_code, status_data in quarterly_stats.items %}
+            <div class="col-lg-2 col-md-3 col-4 mb-2">
+              <div class="px-2">
+                <div class="h6 fw-bold mb-0
+                  {% if status_code == 'offen' %}text-secondary
+                  {% elif status_code == 'teilweise' %}text-warning
+                  {% elif status_code == 'eingereicht' %}text-info
+                  {% elif status_code == 'geprueft' %}text-success
+                  {% elif status_code == 'nachbesserung' %}text-danger
+                  {% elif status_code == 'abgelehnt' %}text-dark
+                  {% endif %}">
+                  {{ status_data.count }}
+                </div>
+                <small class="text-muted">{{ status_data.name }}</small>
+              </div>
+            </div>
+          {% endfor %}
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+
 <div class="card shadow">
   <div class="card-body">
     <div class="table-responsive">
@@ -258,7 +299,12 @@
                 {{ u.get_status_display }}
               </span>
             </td>
-            <td>{{ u.beschreibung }}</td>
+            <td>
+              {{ u.beschreibung }}
+              {% if "Q" in u.beschreibung and "/" in u.beschreibung %}
+                <i class="fas fa-file-contract text-primary ms-2" title="Verknüpft mit Vierteljahresnachweis" data-bs-toggle="tooltip"></i>
+              {% endif %}
+            </td>
             <td>
               <div class="btn-group btn-group-sm" role="group">
                 <a href="{% url 'stiftung:unterstuetzung_edit' pk=u.pk %}" class="btn btn-outline-warning"><i class="fas fa-edit"></i></a>
@@ -424,6 +470,12 @@ document.getElementById('exportForm').addEventListener('submit', function(e) {
 // Initialize counts on page load
 document.addEventListener('DOMContentLoaded', function() {
     updateSelectedCount();
+    
+    // Initialize tooltips for quarterly confirmation indicators
+    var tooltipTriggerList = [].slice.call(document.querySelectorAll('[data-bs-toggle="tooltip"]'));
+    var tooltipList = tooltipTriggerList.map(function (tooltipTriggerEl) {
+        return new bootstrap.Tooltip(tooltipTriggerEl);
+    });
 });
 </script>