NodeJS v24 upgrade

[CopyDemon]

Summary

Upgrade Node.js from 18 to 24 and Storybook from 6.5 to 8, along with the related build-tooling updates (Parcel v2, jsdom) those upgrades required.

Major changes

• Node 18 → 24 — pinned via a new .nvmrc (24) and a new engines field (node >=20); CI workflows and the Dockerfile updated to match. (Neither .nvmrc nor engines existed before.)
• Storybook 6.5 → 8 — @storybook/react ^6.5.3 → ^8.6.18, plus the new unified storybook 8 package.
• Parcel v1 → v2 — removed the deprecated parcel-bundler (^1.12.5) and switched the dev sandbox to parcel (^2.16.4).
• jsdom ^16 → ^26.1.0 — keeps the Jest test environment current with Node 24.

Fixes

• Fixed Jest tests that broke on d3's ESM-only imports (test suite back to passing).
• Fixed npm start failing due to a Parcel target conflict.
• Fixed deploy-storybook: the script still called storybook-to-ghpages, whose package (@storybook/storybook-deployer) was removed during the Storybook 8 upgrade. Replaced it with build-storybook + gh-pages so the command behaves the same (build, then publish storybook-static to GitHub Pages).

#Remaining TODOs (follow-up)

• Fix typo in publish-npm.yml (line 27): npm install ci should be npm ci. It only works today because ci is treated as a package name. (Pre-existing, not introduced here. Not sure if that is a package or the npm ci (install command))
• Address the outstanding npm audit vulnerabilities (separate task). They're almost all in the dev toolchain — published bundles mark these deps as external, so there's no runtime risk to consumers. Do not run npm audit fix: it bumps picomatch, which breaks rollup-plugin-typescript2 and the publish build. These need to be upgraded surgically, one direct dependency at a time, each verified on its own:
  • Breaking API changes: react-tooltip@4 (v5 reworks the whole API), react-graph-vis, uuid@8, axios@0.21
  • Lower-risk: qs, ws, yaml, katex

Checklist

• Google format doc strings added. Check with ruff.
• Type annotations included. Check with mypy.
• Tests added for new features/fixes.
• If applicable, new classes/functions/modules have duecredit @due.dcite decorators to reference relevant papers by DOI (example)

Tip: Install pre-commit hooks to auto-check types and linting before every commit:

pip install -U pre-commit
pre-commit install