Add Geschichte (History) wiki-style feature with reorganized navigation

🆕 NEW FEATURES:
- Wiki-style Geschichte (History) section with rich text editor
- Image upload support for history pages
- Quill.js rich text editor with formatting options
- Slug-based URLs for SEO-friendly history pages
- Image galleries with descriptions and alt-text support

🔧 MODELS:
- GeschichteSeite: Main history pages with rich content
- GeschichteBild: Image attachments for history pages
- Auto-generated slugs, sorting, publishing controls

📝 TEMPLATES:
- geschichte/liste.html: Card-based overview of all history pages
- geschichte/detail.html: Full page view with image gallery
- geschichte/form.html: Rich text editor for creating/editing pages
- geschichte/bild_form.html: Image upload interface

🎨 UI IMPROVEMENTS:
- Reorganized navigation menu into logical groups:
  * Menschen & Finanzen (People & Finance)
  * Immobilien & Land (Real Estate & Land)
  * Verwaltung (Administration)
  * Geschichte (History)
- More compact menu design saving horizontal space
- Better grouping with dropdown headers

🛠️ TECHNICAL:
- Rich text editor with Quill.js integration
- Image upload with validation and optimization
- Permission-based access controls
- Responsive design for all screen sizes
- Proper breadcrumb navigation
- Auto-slug generation from titles

app/stiftung/models.py

@@ -2856,3 +2856,87 @@ class VierteljahresNachweis(models.Model):
             except VierteljahresNachweis.DoesNotExist:
                 pass
         return None
+
+
+class GeschichteSeite(models.Model):
+    """Wiki-style pages for foundation history"""
+    
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    titel = models.CharField(max_length=200, verbose_name="Titel")
+    slug = models.SlugField(max_length=200, unique=True, verbose_name="URL-Slug")
+    inhalt = models.TextField(verbose_name="Inhalt")
+    
+    # Metadata
+    erstellt_am = models.DateTimeField(auto_now_add=True, verbose_name="Erstellt am")
+    aktualisiert_am = models.DateTimeField(auto_now=True, verbose_name="Aktualisiert am")
+    erstellt_von = models.ForeignKey(
+        'auth.User',
+        on_delete=models.SET_NULL,
+        null=True,
+        blank=True,
+        related_name='geschichte_seiten_erstellt',
+        verbose_name="Erstellt von"
+    )
+    aktualisiert_von = models.ForeignKey(
+        'auth.User',
+        on_delete=models.SET_NULL,
+        null=True,
+        blank=True,
+        related_name='geschichte_seiten_aktualisiert',
+        verbose_name="Aktualisiert von"
+    )
+    
+    # Options
+    ist_veroeffentlicht = models.BooleanField(default=True, verbose_name="Veröffentlicht")
+    sortierung = models.IntegerField(default=0, verbose_name="Sortierung")
+    
+    class Meta:
+        verbose_name = "Geschichte Seite"
+        verbose_name_plural = "Geschichte Seiten"
+        ordering = ['sortierung', 'titel']
+    
+    def __str__(self):
+        return self.titel
+    
+    def get_absolute_url(self):
+        from django.urls import reverse
+        return reverse('stiftung:geschichte_detail', kwargs={'slug': self.slug})
+
+
+class GeschichteBild(models.Model):
+    """Images for history pages"""
+    
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    seite = models.ForeignKey(
+        GeschichteSeite,
+        on_delete=models.CASCADE,
+        related_name='bilder',
+        verbose_name="Geschichte Seite"
+    )
+    titel = models.CharField(max_length=200, verbose_name="Bildtitel")
+    bild = models.ImageField(
+        upload_to='geschichte/bilder/%Y/%m/',
+        verbose_name="Bild"
+    )
+    beschreibung = models.TextField(blank=True, verbose_name="Beschreibung")
+    alt_text = models.CharField(max_length=200, blank=True, verbose_name="Alt-Text")
+    
+    # Metadata
+    hochgeladen_am = models.DateTimeField(auto_now_add=True, verbose_name="Hochgeladen am")
+    hochgeladen_von = models.ForeignKey(
+        'auth.User',
+        on_delete=models.SET_NULL,
+        null=True,
+        blank=True,
+        verbose_name="Hochgeladen von"
+    )
+    
+    sortierung = models.IntegerField(default=0, verbose_name="Sortierung")
+    
+    class Meta:
+        verbose_name = "Geschichte Bild"
+        verbose_name_plural = "Geschichte Bilder"
+        ordering = ['sortierung', 'titel']
+    
+    def __str__(self):
+        return f"{self.titel} ({self.seite.titel})"