feat!: Upgrade Node.js dependencies (Actions and Supported versions)

[brandonlenz]

Summary

• Breaking change: Drops support for Node 20 (EOL)
• Updates the development version to Node 26
• Updates actions to use v5 Node.js actions since v4 actions will be EOL by September.

TODO: Once approved, in order to merge, update repository settings to

• require Node 26 tests to pass
• remove the requirement for Node 20 tests to pass

See also: https://nodejs.org/en/about/previous-releases

Related Issues or PRs

closes: #3458

How To Test

• Install node 26 locally, run tests and storybook locally
• Verify CI checks using v5 runners pass

Screenshots (optional)

Author & Maintainer checklist

• Is this is a breaking change?
  • Yes, and I accounted for the breaking changes according to the linked documentation
  • No
• Once merged, add the PR and Issue author(s) as a contributor(s) via the all-contributors bot

[github-actions]

	Warnings
⚠️	Changes were made to package.json, but not to yarn.lock - Perhaps you need to run yarn install?

Generated by 🚫 dangerJS against 587d0a1

[brandonlenz]

TODO: Once approved, in order to merge, update repository settings to

• require Node 26 tests to pass
• remove the requirement for Node 20 tests to pass

[brandonlenz]

@jsclarridge can I tag you in for review on this one?