Add color overlay settings for link buttons

- Added link_overlay_enabled, link_overlay_color, link_overlay_opacity to DesignSettings model
- Created migration 0008 for new fields
- Updated CustomizationPanel with link overlay controls section
- Added validation for new overlay settings in serializer
- Updated PublicDesignSettingsSerializer to include overlay settings
- Applied link overlay to all ExpandableGroup components in public page
- Added preview in customization panel for link overlay effect

backend/customization/serializers.py

@@ -36,6 +36,9 @@ class DesignSettingsSerializer(serializers.ModelSerializer):
             'group_description_text_color',
             'body_font_family',
             'heading_font_family',
+            'link_overlay_enabled',
+            'link_overlay_color',
+            'link_overlay_opacity',
             'updated_at'
         ]
         read_only_fields = ['id', 'updated_at', 'background_image_url']
@@ -261,6 +264,26 @@ class DesignSettingsSerializer(serializers.ModelSerializer):
             raise serializers.ValidationError('ID шаблона слишком длинный')
         return value
 
+    def validate_link_overlay_color(self, value):
+        """
+        Валидация цвета перекрытия кнопок ссылок
+        """
+        if not value.startswith('#') or len(value) != 7:
+            raise serializers.ValidationError('Цвет должен быть в формате #RRGGBB')
+        try:
+            int(value[1:], 16)
+        except ValueError:
+            raise serializers.ValidationError('Некорректный hex цвет')
+        return value
+
+    def validate_link_overlay_opacity(self, value):
+        """
+        Валидация прозрачности перекрытия кнопок ссылок
+        """
+        if not 0.0 <= value <= 1.0:
+            raise serializers.ValidationError('Прозрачность должна быть между 0.0 и 1.0')
+        return value
+
 
 class PublicDesignSettingsSerializer(serializers.ModelSerializer):
     """
@@ -273,8 +296,28 @@ class PublicDesignSettingsSerializer(serializers.ModelSerializer):
         fields = [
             'theme_color',
             'background_image_url',
+            'dashboard_layout',
+            'groups_default_expanded',
+            'show_group_icons',
+            'show_link_icons',
+            'dashboard_background_color',
             'font_family',
-            'custom_css'
+            'header_text_color',
+            'group_text_color',
+            'link_text_color',
+            'group_overlay_enabled',
+            'group_overlay_color',
+            'group_overlay_opacity',
+            'show_groups_title',
+            'group_description_text_color',
+            'body_font_family',
+            'heading_font_family',
+            'cover_overlay_enabled',
+            'cover_overlay_color',
+            'cover_overlay_opacity',
+            'link_overlay_enabled',
+            'link_overlay_color',
+            'link_overlay_opacity'
         ]
 
     def get_background_image_url(self, obj):