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/serializers.py

@@ -19,6 +19,7 @@ class UserSerializer(serializers.ModelSerializer):
     """
 
     avatar_url = serializers.SerializerMethodField()
+    display_name = serializers.SerializerMethodField()
 
     class Meta:
         model = User
@@ -26,8 +27,7 @@ class UserSerializer(serializers.ModelSerializer):
             "id",
             "username",
             "email",
-            "first_name",
-            "last_name",
+            "display_name",
             "date_joined",
             "is_active",
             "avatar_url",
@@ -40,6 +40,10 @@ class UserSerializer(serializers.ModelSerializer):
             return obj.profile.avatar.url
         return None
 
+    def get_display_name(self, obj) -> str:
+        """Get user display name"""
+        return obj.get_display_name()
+
 
 class LoginSerializer(serializers.Serializer):
     """
@@ -82,14 +86,14 @@ class SignupSerializer(serializers.ModelSerializer):
         fields = [
             "username",
             "email",
-            "first_name",
-            "last_name",
+            "display_name",
             "password",
             "password_confirm",
         ]
         extra_kwargs = {
             "password": {"write_only": True},
             "email": {"required": True},
+            "display_name": {"required": True},
         }
 
     def validate_email(self, value):