Preview for 26.04 release notes and refresh library source

[nrichers]

Pull Request Description

What and why?

This PR provides a preview for our 26.04 release notes and refreshes our library source.

How to test

What needs special review?

Dependencies, breaking changes, and deployment notes

Release notes

Checklist

• What and why
• Screenshots or videos (Frontend)
• How to test
• What needs special review
• Dependencies, breaking changes, and deployment notes
• Labels applied
• PR linked to Shortcut
• Unit tests added (Backend)
• Tested locally
• Documentation updated (if required)
• Environment variable additions/changes documented (if required)

[github-actions]

PR Summary

This PR updates the recommended Python version ranges in various documentation files and notebooks from "Python 3.8 <= x <= 3.11" (or similar variants) to "Python 3.8 <= x <= 3.14". The changes span multiple files including GitHub workflow configuration for the docs site, Jupyter notebooks (both R Markdown and ipynb files) used for quickstarts, model development, model validation, use cases, and tutorials. Additionally, in the workflow file (.github/workflows/validate-docs-site.yaml) a new branch reference (ref: nrichers/sc-15270/release-notes-for-26-04) is added to ensure that release notes are checked out from the updated branch. Overall, the modifications are documentation-oriented and adjust version support recommendations without altering the core functionality of the library or tests.

Key functional changes:

• Update of the recommended Python version range to include Python 3.14 in all relevant documentation and alert banners.
• Inclusion of a specific Git reference in the workflow for the release notes repository.
• No modifications to algorithm logic or functionality; changes are purely to guidance and workflow configuration.

Test Suggestions

• Run the documentation build pipeline to ensure that all version banners display correctly.
• Execute the notebooks (both Python and R versions) in a Python 3.14 environment to verify compatibility.
• Trigger the GitHub workflow to confirm that the new release notes reference is correctly checked out and that the docs site validation passes.