js/install.json is incompatible with the lastest `jupyterlab`

 lastest `jupyterlab` is expecting "packageName"(jupyterlab-plotly) and "packageManager"(python) in this file. Otherwise quite a few subcommand would complain like this:

<img width="1627" height="299" alt="Image" src="https://github.com/user-attachments/assets/f4077f22-eb77-4402-b497-b4b057f490e5" />

It's trivial but annoying. Could you please fix it?