Add support for drag and drop while editing message.

[nakul-py]

Adding support for drag and drop files while editing messages in chat input.

Screencast.From.2025-09-28.20-29-12.mp4

• Closes Drag and drop on message edition #279

[github-actions]

👈 Launch a Binder on branch nakul-py/jupyter-chat/attachment

[brichet]

Thanks @nakul-py for working on this.

It seems that it does not handle several editions, neither dropping the file to the main input while editing.

output.webm

I wonder if there is a way to drop the file in any input and add the attachment to that input.

[nakul-py]

It seems that it does not handle several editions, neither dropping the file to the main input while editing.

Gonna fixing it :). Thanks for Attention!

[nakul-py]

I wonder if there is a way to drop the file in any input and add the attachment to that input.

Yes! Each input now has a unique data-input-id, so dropping a file automatically adds the attachment to the correct main-input or edition.

[nakul-py]

@brichet Any suggestion to make code changes more robust.