[Windows app] Previously read completed threads become unread after restart and outrank active threads

What version of the Codex App are you using?

26.730.7989.0

What platform is your computer?

Windows 10 Enterprise 22H2 (build 19044), x64

What issue are you seeing?

Since approximately August 2–5, 2026 (Asia/Shanghai, UTC+8), restarting the Codex desktop app causes some long-completed, previously read threads to become unread again.

This also makes the sidebar appear incorrectly ordered: with the default Priority sorting, those old completed-but-reintroduced-as-unread threads jump above threads that are currently active/running. The affected threads may be in different projects.

The main bug appears to be that read/unread state is not stable across a full app restart. The sorting symptom is amplified because Priority ranks unread threads ahead of active threads.

The current Projects sidebar layout does not expose a sort control, so the user cannot switch to Last updated through the visible UI.

No task content appears to be lost.

Steps to reproduce

1. Open/read completed threads until their unread indicators are cleared.
2. Keep at least one other thread active/running (ideally across multiple projects).
3. Fully quit the Codex desktop app.
4. Reopen the app.
5. Observe that some old completed threads are marked unread again.
6. Observe that Priority sorting places those threads above currently active threads.

This can affect a subset of old completed threads after each restart rather than every thread.

Expected behavior

• A completed thread that has been read should remain read after restarting the app.
• Priority sorting should not promote old completed threads above active threads because of an incorrectly restored unread state.
• If Priority ordering is intentional, the Projects sidebar should expose the supported Last updated sorting option as a user-accessible workaround.

Additional diagnostic information

Sanitized, read-only inspection of the current packaged renderer and local preferences found:

• Persisted sidebar settings were chatSortMode: "priority" and projectSortMode: "priority".
• The Priority attention order is waiting → unread → active → idle, which explains why a falsely restored unread state outranks an active thread.
• The renderer supports an internal updated_at sort mode.
• In the current Projects navigation layout, the options menu is invoked in an organize-only mode, so sorting controls are hidden.
• Setting both sort modes to updated_at avoids the misleading ordering, but it does not fix the unread-state reset itself.

The cause of the unread-state rehydration/reset has not been identified.

Related but not duplicate: #35228, #30855, #33077.

No raw thread IDs, thread titles, local paths, session files, or databases are attached.