Open WebUI: Any authenticated user can start a non-terminating request via a folder parent cycle

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.10.0 until 0.11.1, POST /api/v1/folders/{id}/update/parent allowed a user to place a folder under itself or one of its descendants, while the folder tree walks used by DELETE /api/v1/folders/{id} and POST /api/v1/folders/{id}/read did not track visited folder identifiers. An authenticated user could persist a parent cycle and start a request that consumed CPU and memory indefinitely, with the condition remaining stored until repaired. This issue is fixed in version 0.11.1.