Refactor user account system and remove moderation integration

- Remove first_name and last_name fields from User model
- Add user deletion and social provider services
- Restructure auth serializers into separate directory
- Update avatar upload functionality and API endpoints
- Remove django-moderation integration documentation
- Add mandatory compliance enforcement rules
- Update frontend documentation with API usage examples

backend/apps/accounts/services.py

@@ -28,8 +28,6 @@ class UserDeletionService:
             username=cls.DELETED_USER_USERNAME,
             defaults={
                 "email": cls.DELETED_USER_EMAIL,
-                "first_name": "",
-                "last_name": "",
                 "is_active": False,
                 "is_staff": False,
                 "is_superuser": False,
@@ -177,7 +175,11 @@ class UserDeletionService:
             return False, "Cannot delete the system deleted user placeholder"
 
         if user.is_superuser:
-            return False, "Cannot delete superuser accounts"
+            return False, "Superuser accounts cannot be deleted for security reasons. Please contact system administrator or remove superuser privileges first."
+
+        # Check if user has critical admin role
+        if user.role == User.Roles.ADMIN and user.is_staff:
+            return False, "Admin accounts with staff privileges cannot be deleted. Please remove admin privileges first or contact system administrator."
 
         # Add any other business rules here