Revert "revert: revert human input relevant code (#31766)"

This reverts commit 90fe9abab7.

api/libs/flask_utils.py

@@ -1,12 +1,15 @@
 import contextvars
 from collections.abc import Iterator
 from contextlib import contextmanager
-from typing import TypeVar
+from typing import TYPE_CHECKING, TypeVar
 
 from flask import Flask, g
 
 T = TypeVar("T")
 
+if TYPE_CHECKING:
+    from models import Account, EndUser
+
 
 @contextmanager
 def preserve_flask_contexts(
@@ -64,3 +67,7 @@ def preserve_flask_contexts(
         finally:
             # Any cleanup can be added here if needed
             pass
+
+
+def set_login_user(user: "Account | EndUser"):
+    g._login_user = user