[macOS Desktop 26.810.52044] Update hides legacy local history, Remote shows only active task, and renamed titles disappear

Summary

After a recent ChatGPT/Codex Desktop update, local Codex history and manually renamed conversation titles became inconsistent across Desktop and iPhone Remote.

The underlying local data is still present, but the default Desktop/Remote listing returns only a small subset of threads. iPhone Remote shows only the current active task. In addition, previously renamed conversation titles no longer appear after the sidebar state is refreshed.

This looks like a regression in history/sidebar metadata migration or provider filtering, not intentional deletion.

Related issues: #25463 and #34446.

Environment

• Platform: macOS 26.5 (Apple Silicon)
• ChatGPT/Codex Desktop: 26.810.52044
• Bundled Codex CLI: 0.148.0-alpha.9
• iPhone client: ChatGPT Remote connected to the same Desktop host

Observed behavior

1. The local thread catalog still contains 64 historical entries, with non-empty display titles and no entries marked missing.
2. The local thread store contains 65 thread rows; the conversation bodies are still present.
3. The default thread/list result returns only 5 openai_http threads.
4. Requesting the same list explicitly for the legacy openai provider returns 48 additional threads.
5. On iPhone Remote, only the current active task is visible; the historical threads are absent.
6. The cached sidebar state previously contained 60 conversation title entries. After the update/state refresh, it contains only 20. The missing entries include user-renamed titles.
7. Restarting the Desktop app re-fetches the truncated list and overwrites the local sidebar cache, so restoring an old cache is not a durable workaround.

Steps to reproduce

1. Use Codex Desktop on macOS with an existing local history containing older threads and renamed conversation titles.
2. Update/restart the ChatGPT/Codex Desktop app.
3. Open the Desktop history/sidebar and connect from the ChatGPT iPhone app using Remote.
4. Observe that older history and renamed titles are missing or replaced, while local thread data remains on disk.
5. Compare the default thread list with explicit provider filters.

Expected behavior

• All non-archived local Codex threads should remain listed after update/restart.
• Thread titles, including user renames, should remain stable.
• Remote should show the same eligible historical thread list as the Desktop host.
• A provider migration must not silently exclude legacy-provider threads from the default listing.

Actual behavior

• The default list omits most historical threads.
• Remote shows only the active task.
• Renamed conversation-title metadata is reduced/overwritten when the app refreshes its sidebar state.
• The data appears to remain locally recoverable, but the UI and Remote list are incomplete.

Requested investigation

1. Check Desktop migration/filtering between openai and openai_http model providers.
2. Ensure default thread listing includes compatible legacy local threads after an update.
3. Check why sidebar title/rename metadata is truncated and then overwritten by sync.
4. Ensure iPhone Remote uses the same eligible thread set as the host Desktop.
5. Provide a supported reindex/repair path that does not require editing local SQLite or global state manually.

I can provide additional sanitized counts or logs if useful, but I will not publish private transcripts, account information, or local database files.