chore: retire demo technical debt

backend/app/api/memories.py

@@ -1,7 +1,7 @@
 """Memory management APIs."""
 
 from fastapi import APIRouter, Depends, HTTPException
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.core.deps import require_user
@@ -13,10 +13,12 @@ from app.services.memory_service import MemoryType
 router = APIRouter()
 
 
-class MemoryItemResponse(BaseModel):
-    """Memory item response."""
-
-    id: str
+class MemoryItemResponse(BaseModel):
+    """Memory item response."""
+
+    model_config = ConfigDict(from_attributes=True)
+
+    id: str
     type: str
     value: dict
     base_weight: float
@@ -24,11 +26,8 @@ class MemoryItemResponse(BaseModel):
     created_at: str
     last_used_at: str | None
 
-    class Config:
-        from_attributes = True
-
-
-class MemoryListResponse(BaseModel):
+
+class MemoryListResponse(BaseModel):
     """Memory list response."""
 
     memories: list[MemoryItemResponse]