Swap the Jupyter Notebook Renderers extension from built in to bootstrapped

[melissa-barca]

System details: Desktop

Positron and OS details:

2025.03

Interpreter details:

N/A

Describe the issue:

In #6403 we introduced the concept of "bootstrapped" extensions, which bundles several previously built-in extensions with Positron and installs them on the application's first launch. We were not able to include the Jupyter Notebook Renderers extension in this group because it exposed itself as an undocumented dependency of the positron-ipywidgets extension via our e2e tests, see discussion: #6403 (review)

Because the extension is installed at application launch, it requires a reload of Positron before it is fully available to positron-ipywidgets. Below is what the extension looks like after being installed on app launch instead of built-in:

This only affects the initial run on desktop dev builds, but that is where our tests run.

Expected or desired behavior:

Feature to be implemented with passing e2e tests.

• Open the Developer Tools console by running the Developer: Toggle Developer Tools command from the Command Palette
• Open the relevant Output Channel logs by utilizing this guide: https://positron.posit.co/troubleshooting.html

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[seeM]

The positron-ipywidgets extension assumes that RequireJS is loaded in the notebook/plot webview.

Here's how that happens:

The Jupyter Notebook Renderers extension contributes a notebook preload script for the jupyter-notebook notebook type, which gets loaded by notebook/plot webviews.

The preload script has an empty activate() function and exists solely to bundle jQuery and RequireJS.

The bundling is done with webpack. Here is the preload webpack config, and here is how jQuery and RequireJS are bundled.

We could bundle RequireJS ourselves, either in the existing notebook renderer (positron-ipywidgets/renderer) or in a new notebook preload.

I think the main difference between renderers and preloads is that preloads are always loaded for the specified notebook type (e.g. jupyter-notebook) but renderers are only loaded on usage or on explicit requirement (package.json contributes.notebookRenderer[0].dependencies).