Windows desktop 26.930.3930.0: local project chats fail as helpers recreate mirror folder locks

Finding: In an external report on Windows desktop Codex (Microsoft Store OpenAI.Codex 26.930.3930.0, observed 2026-10-09), starting a new local Work chat in an existing project intermittently fails with the UI error "Could not use this project for a local chat" (https://github.com/openai/codex/issues/52695). This is an external report only; KFA did not reproduce it. Reported evidence: Desktop logs repeatedly show "ChatGPT project context sync failed" with stage=filesystem and no further detail, with a failure logged at 2026-10-09T20:14:24.531Z. The affected mirror lives under the user's .codex\.chatgpt-projects\<project-id> directory. A handle-only probe using CreateFileW with DELETE access initially returned Windows error 32 (sharing violation). Six node.exe/node_repl.exe helpers had that mirror directory as their current working directory while project chats were idle. After the reporter stopped those helpers, the probe succeeded. After a retry through the UI, the error returned, new helpers again held the directory, and the probe again returned error 32. Directory access alone therefore did not establish successful chat creation (https://github.com/openai/codex/issues/52695). Reported implementation inspection: The reporter says the installed bundle's sync routine stages a replacement mirror, renames the existing mirror to a previous-directory path, then renames the staged directory into place. They infer a conflict between helper working-directory handles and the mirror replacement. They state the actual failing syscall was not traced, so this remains an inference and not a confirmed cause. Status: The only comment is an automated potential-duplicate notice referencing #52333. No maintainer confirmation of cause, fix, or release appears in the supplied context. The reporter links related issues #44736, #45596 and #34499 and describes this as the same failure class on a later build, not a confirmed new regression. A configuration workaround from #44736 was not applied or validated. Limitations: Single report; subscription and exact Windows build were not collected; comment coverage is partial. Manual helper termination is only temporary and did not restore chat creation in the reported retry. Diagnostically, if you see stage=filesystem with this error on Windows, checking whether helper processes hold the mirror as their working directory is a source-reported lead, not a proven cause.