Support Notebook 7

[jtpio]

Fixes #504

Rely on the new (optional) currentChanged signal added to the JupyterFrontend.IShell interface in JupyterLab 4.2.0: jupyterlab/jupyterlab#15449. Which requires bumping the @jupyterlab/application package to ^4.2.0.

This should not change anything for JupyterLab users. However since Notebook 7 also implement this signal, this makes it possible to use Jupyter AI in Notebook 7

Changes

• Bump @jupyterlab packages to 4.2
• Update docs to mention the extension is compatible with Notebook 7.2.0+

Screenshots

[dlqqq]

@jtpio Thank you so much for exploring how to support this feature! I'm excited to be able to use Jupyter AI in Notebook now.

BTW, #828 calls a few more JupyterLab APIs to implement error output detection, which may impact this PR. Since #828 changes more significant lines of code, I believe it will be easier to have #828 reviewed & merged first before addressing potential conflicts in this PR. I will help with the rebase if the conflicts are clear for me to resolve independently.

[jtpio]

BTW, #828 calls a few more JupyterLab APIs to implement error output detection, which may impact this PR. Since #828 changes more significant lines of code, I believe it will be easier to have #828 reviewed & merged first before addressing potential conflicts in this PR. I will help with the rebase if the conflicts are clear for me to resolve independently.

Looks like there were no conflicts after the merge of #828 👍

[dlqqq]

@jtpio Awesome work, thank you so much! Tested & verified locally in both JupyterLab and Jupyter Notebook. Looking forward to making this available to users.