chore: retire demo technical debt

backend/app/api/universes.py

@@ -3,7 +3,7 @@
 from typing import Any
 
 from fastapi import APIRouter, Depends, HTTPException, status
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -42,6 +42,8 @@ class AchievementCreate(BaseModel):
 class StoryUniverseResponse(BaseModel):
     """Universe response."""
 
+    model_config = ConfigDict(from_attributes=True)
+
     id: str
     child_profile_id: str
     name: str
@@ -50,9 +52,6 @@ class StoryUniverseResponse(BaseModel):
     world_settings: dict[str, Any]
     achievements: list[dict[str, Any]]
 
-    class Config:
-        from_attributes = True
-
 
 class StoryUniverseListResponse(BaseModel):
     """Universe list response."""