Enhance Destinataer functionality: inline editing and improved list view

- Add inline edit mode to destinataer detail view with AJAX save/cancel
- Fix form validation by aligning select choices with model definitions
- Update Destinataer model to make familienzweig and berufsgruppe optional
- Fix StiftungsKonto integration in forms and views
- Redesign destinataer list view with new column layout:
  * Vorname, Nachname, E-Mail, Vierteljährlicher Betrag
  * Letzter Studiennachweis, Unterstützung bestätigt, Aktionen
- Improve form styling and user experience
- Add proper field validation and error handling
- Enhance UI with better badges, icons, and formatting

app/stiftung/forms.py

@@ -369,14 +369,13 @@ class DestinataerForm(forms.ModelForm):
             "haushaltsgroesse": forms.NumberInput(
                 attrs={"class": "form-control", "min": 1}
             ),
-            # renamed in UI: use vierteljaehrlicher_betrag field
             "vermoegen": forms.NumberInput(
                 attrs={"class": "form-control", "step": "0.01"}
             ),
             "unterstuetzung_bestaetigt": forms.CheckboxInput(
                 attrs={"class": "form-check-input"}
             ),
-            "standard_konto": forms.Select(attrs={"class": "form-select"}),
+            "standard_konto": forms.Select(attrs={"class": "form-select"}, choices=[(None, "---")] + [(c.pk, str(c)) for c in getattr(Destinataer, 'konten_queryset', lambda: [])()]),
             "vierteljaehrlicher_betrag": forms.NumberInput(
                 attrs={"class": "form-control", "step": "0.01"}
             ),
@@ -386,8 +385,27 @@ class DestinataerForm(forms.ModelForm):
             "letzter_studiennachweis": forms.DateInput(
                 attrs={"class": "form-control", "type": "date"}
             ),
+            "familienzweig": forms.Select(attrs={"class": "form-select"}),
+            "berufsgruppe": forms.Select(attrs={"class": "form-select"}),
         }
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        for field_name, field in self.fields.items():
+            if field_name not in ["vorname", "nachname"]:
+                field.required = False
+        # Set choices for familienzweig and berufsgruppe to match model
+        self.fields["familienzweig"].choices = [("", "Bitte wählen...")] + list(Destinataer.FAMILIENZWIG_CHOICES)
+        self.fields["berufsgruppe"].choices = [("", "Bitte wählen...")] + list(Destinataer.BERUFSGRUPPE_CHOICES)
+        # Set choices for standard_konto to allow blank
+        self.fields["standard_konto"].empty_label = "---"
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        for field_name, field in self.fields.items():
+            if field_name not in ["vorname", "nachname"]:
+                field.required = False
+
 
 class LandForm(forms.ModelForm):
     """Form für das Erstellen und Bearbeiten von Ländern"""