Refactor API structure and add comprehensive user management features

- Restructure API v1 with improved serializers organization
- Add user deletion requests and moderation queue system
- Implement bulk moderation operations and permissions
- Add user profile enhancements with display names and avatars
- Expand ride and park API endpoints with better filtering
- Add manufacturer API with detailed ride relationships
- Improve authentication flows and error handling
- Update frontend documentation and API specifications

backend/apps/api/v1/auth/serializers.py

@@ -75,6 +75,7 @@ class UserOutputSerializer(serializers.ModelSerializer):
     """User serializer for API responses."""
 
     avatar_url = serializers.SerializerMethodField()
+    display_name = serializers.SerializerMethodField()
 
     class Meta:
         model = UserModel
@@ -87,9 +88,14 @@ class UserOutputSerializer(serializers.ModelSerializer):
             "date_joined",
             "is_active",
             "avatar_url",
+            "display_name",
         ]
         read_only_fields = ["id", "date_joined", "is_active"]
 
+    def get_display_name(self, obj):
+        """Get the user's display name."""
+        return obj.get_display_name()
+
     @extend_schema_field(serializers.URLField(allow_null=True))
     def get_avatar_url(self, obj) -> str | None:
         """Get user avatar URL."""