Adding editors to the "Open in" dropdown menu

What version of the Codex App are you using (From “About Codex” dialog)?

macOS app - Version 26.224.1209 (697)

What subscription do you have?

Plus

What platform is your computer?

Darwin 25.1.0 arm64 arm

What issue are you seeing?

The "Open in" drop down menu features many editors.
However, I want to use Emacs.
There is no obvious way of adding apps to the drop down menu.

What steps can reproduce the bug?

Open the app. Click the drop down menu.

<img width="188" height="301" alt="Image" src="https://github.com/user-attachments/assets/99b89854-bd48-45b1-93d1-a929580a857e" />

What is the expected behavior?

Seeing Emacs.

Ideally an "Add editor/preview" at the bottom.

Additional information

_No response_