VS Code Remote SSH fails on multi-user Linux host

What version of the IDE extension are you using?

openai.chatgpt 26.325.21211

What subscription do you have?

Plus

Which IDE are you using?

VS Code

What platform is your computer?

Local: Windows, Remote SSH host: Linux (multi-user shared machine)

What issue are you seeing?

Codex VS Code extension fails under Remote SSH on a multi-user Linux host because it tries to create its IPC socket under a global shared directory:

/tmp/codex-ipc/ipc-<uid>.sock

The extension panel loads, but the chat input/composer does not appear. In the Codex output channel, the extension logs:

[IpcRouterManager] Server error errorCode=EACCES errorMessage="listen EACCES: permission denied /tmp/codex-ipc/ipc-33243.sock"

### What steps can reproduce the bug?

1. Use VS Code on Windows with the OpenAI Codex extension installed locally.
2. Connect from VS Code to a shared Linux machine via Remote SSH.
3. Install/enable the OpenAI Codex extension on the remote SSH host as well.
4. Ensure another user on the same Linux machine has already created `/tmp/codex-ipc` with ownership/permissions that are not writable by the current user.
5. Open the Codex sidebar in the Remote SSH window.
6. Observe that the panel shell loads but the chat input/composer does not appear.
7. Check the Codex output channel and see:
   `listen EACCES: permission denied /tmp/codex-ipc/ipc-<uid>.sock`

### What is the expected behavior?

Codex should open and function normally in VS Code Remote SSH on a shared Linux machine. The extension should use a per-user IPC path like `~/tmp/codex-ipc` instead of a global `/tmp/codex-ipc` directory, so the backend can start successfully and the chat input appears as expected.

### Additional information

_No response_