Fix disabled date field to show current value when editing

- Set initial value for disabled faellig_am field in auto-generated payments
- Explicitly set widget value attribute to display current date
- Ensures the field shows the correct date even when disabled

app/stiftung/forms.py

@@ -1005,6 +1005,11 @@ class DestinataerUnterstuetzungForm(forms.ModelForm):
                 self.is_auto_generated = True
                 self.fields['faellig_am'].disabled = True
                 self.fields['faellig_am'].help_text = "Fälligkeitsdatum wird automatisch basierend auf Quartal berechnet"
+                # Ensure the initial value is set for disabled field and widget shows the value
+                self.fields['faellig_am'].initial = self.instance.faellig_am
+                self.fields['faellig_am'].widget.attrs.update({
+                    'value': self.instance.faellig_am.strftime('%Y-%m-%d') if self.instance.faellig_am else ''
+                })
     
     def clean(self):
         cleaned_data = super().clean()