feat(cli): add mention view shortcuts

[Oerum]

Description

Currently there is no fast way to open files or their containing folders directly from the @ mention view suggestions list.

Proposed Solution

Add the following keyboard shortcuts when navigating the mention view suggestions:

• Ctrl+X: Open the selected file in the external editor
• Alt+O: Open the directory containing the selected file

[jacob314]

I like this idea but two concerns:
ctrl-X already opens the prompt in the external editor.
Alt+O cannot be supported reliably on mac as users may reasonably want to type ø and Macs make it hard to distinguish the two on all terminals.

We're basically all out of valid keyboard shortcuts so would suggest we need an approach that doesn't require custom shortcuts or wait for custom shortcut support.
Fyi @scidomino

[Oerum]

Ctrl-X should still support opening the prompt in the external editor, it only opens the file when you hover it in the (@) mention view.

[cocosheng-g]

Triage Summary

This is a well-defined feature request to add shortcuts for opening files and directories directly from the mention view. It improves usability and is a great candidate for a community contribution. Categorized as Help-wanted.

@Oerum, apologies! It looks like your PR #20502 was incorrectly closed by our bot. I have reopened it and assigned this issue to you. Would you like to continue working on it?

[scidomino]

Please don't implement Alt-O. Alt keys are poorly supported in mac.

[Adib234]

Thank you for bringing this to our attention. Right now, our engineering team is focusing all resources on critical system maintenance and core stability. Because of this, we don't have immediate plans to address this specific issue, but we truly appreciate you flagging it for us.