Adding ability to update / patch by sku, adding uniqueness constraint violation checks

app/api/users.py

@@ -82,6 +82,12 @@ async def update_user(
             status_code=status.HTTP_404_NOT_FOUND, detail="User not found"
         )
     changes = payload.model_dump(exclude_unset=True)
+    if "email" in changes:
+        existing = await user_crud.get_by_email(db, changes["email"])
+        if existing is not None and existing.id != target.id:
+            raise HTTPException(
+                status_code=status.HTTP_409_CONFLICT, detail="Email already registered"
+            )
     target = await user_crud.update(db, target, changes)
     await audit_crud.log(
         db,