fix(tests): stabilize escalation SSE backend tests

Co-Authored-By: Codex <noreply@openai.com>

backend/app/api/endpoints/session_handoffs.py

@@ -156,7 +156,10 @@ _QUEUE_GET_TIMEOUT_S = 25  # < heartbeat so heartbeat fires reliably
 @queue_router.get("/escalations/stream")
 async def stream_escalations(
     request: Request,
-    current_user: Annotated[User, Depends(require_engineer_or_admin)],
+    current_user: Annotated[
+        User,
+        Depends(require_engineer_or_admin, scope="function"),
+    ],
 ):
     """SSE stream of new escalation arrivals for the current user's account.