[GSoC 25] Proposal: Enable pip-based installation for Beam JupyterLab SidePanel

[chen canyu]

Hi Beam Devs,
I'm currently working on improving the usability and packaging experience
of the Beam JupyterLab Sidepanel extension.
Today, installing JupyterLab extensions typically requires calling jupyter
labextension install, which:

   - is deprecated in JupyterLab 4.x,


   - adds friction for end users,


   - and is not compatible with modern Python packaging practices.

To address this, I opened a PR that adds support for pip-based installation
of the apache-beam-jupyterlab-side panel extension:
🔗 PR: https://github.com/apache/beam/pull/35399
With this change, users can simply run:
```bash
pip install apache-beam-jupyterlab-sidepanel
```
…and the extension is immediately available in JupyterLab — no manual
labextension install step required.
This is implemented using pyproject.toml, hatchling, and
hatch-jupyter-builder, following the JupyterLab prebuilt extension standard.
The goal is to make the sidepanel more accessible to users (especially new
ones), reduce installation errors, and improve integration with CI/CD
systems.
If you have thoughts on this approach — naming, packaging standards, or
longer-term integration into Beam releases — I’d appreciate the feedback.
Thanks,
Canyu