Support drag-and-drop file attachment as chat context in Codex IDE extension

What variant of Codex are you using?

IDE Extension (VS Code)

What feature would you like to see?

I would like to request support for dragging and dropping files into the Codex chat input to attach them as context.

In GitHub Copilot Chat, I can drag a file from the editor or file explorer into the chat box, and it becomes attached as context. This is very convenient when working with a large codebase because I can quickly provide the exact files I want the assistant to analyze.

Currently, in Codex, I usually have to type @filename or manually reference the file. This works, but it is less convenient when:

• The file path is deeply nested.
• Multiple files have similar names.
• I want to attach several files quickly.
• I am working in a large project and do not remember the exact file name.

It would be very helpful if Codex supported a UI flow such as:

• Drag and drop a file into the chat input.
• Show the attached file as a context chip.
• Allow removing attached files before sending.
• Support attaching multiple files as context.

This would make Codex much easier to use for real coding workflows, especially when debugging or asking questions about specific files in a large project.

<img width="655" height="1011" alt="Image" src="https://github.com/user-attachments/assets/da24f76a-189b-4279-97d7-0892ef00fc17" />

<img width="601" height="1028" alt="Image" src="https://github.com/user-attachments/assets/a462d12e-790c-46f0-9114-3ed11a87fb8a" />

Additional information

GitHub Copilot Chat already has a similar “Attach File as Context” workflow, which makes it easy to add files directly into the chat context. I think adding a similar interaction to the Codex IDE extension would improve usability and reduce friction when working with large repositories.