Add visualization framework interface to cell-based markdown editor

[guerler]

Requires #19835. See discussion regarding visualizations in pages in #19226.

This PR integrates an interface for our new visualization framework into the cell-based Markdown editor. Only fully packaged, standalone visualizations—published as npm packages in accordance with our new framework—can be used in pages and reports. This ensures stability, preventing visualizations from breaking due to Galaxy updates or build system limitations. Additionally, this PR enables the cell-based Markdown editor for workflow reports and lays the groundwork for workflow-specific visualizations by integrating Vega and Vitessce cell/block types.

Usage in Pages (with preview):

Screen.Recording.2025-03-19.at.7.01.45.PM.mov

Usage in Workflow Reports (without preview):

Screen.Recording.2025-03-20.at.9.43.16.AM.mov

How to test the changes?

(Select all options that apply)

• I've included appropriate [automated tests (https://docs.galaxyproject.org/en/latest/dev/writing_tests.html).
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[jmchilton]

Thanks for your detailed response on #19226 (comment) - I hadn't seen that until just now. Umm... I think you've addressed my concerns well enough - I still wish we had generic components for a set of charts even if ad hoc plugins are needed generally... but also you're right that these plugins are packaged and installed in a much more robust and forward/backward compatible way than they used to be and maybe this is enough and enough for now.

I think this PR is really beautiful and exciting.

[jmchilton]

Given that galaxy encompasses all sorts of kinds of plugins - it seems disjoint that visualization is sort of standalone - wouldn't this syntax feel more internally consistent if it was galaxy_visualization as the syntax marker. It is a small point though - I think this could be fine despite the brain scratch it gives me.

[guerler]

Good point — but I think visualization is better here since we don’t actually use any galaxy_-prefixed namespaces elsewhere. That said, I’m open to changing it in a follow-up if it keeps feeling off.

[guerler]

@jmchilton thank you so much for your review!