Feature Request: Add optional user notification when Codex completes a task

What feature would you like to see?

Description
It would be helpful if Codex could optionally let the user know when a run is complete. This is especially useful when tasks take a while and the developer has switched focus (e.g. working in Cursor or VS Code).

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Proposed solution
• Add a --notify flag to the CLI that shows a system notification when Codex exits.
• Alternatively, print a clear marker (e.g. <<<CODEX_DONE>>>) at the end of execution so external tools can hook into it.

Both options would be backwards-compatible and off by default.

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Use case
• Developers running long Codex tasks won’t need to constantly check the terminal/IDE.
• Makes it easier to integrate with editor extensions or shell wrappers that already support notifications.

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Next steps
Opening this issue to see if the team is open to the idea. If there’s alignment, I’d be happy to put together a small PR for review.

Are you interested in implementing this feature?

_No response_

Additional information

_No response_