chore(nodejs): upgrade to Storybook 8

[dhess]

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[dhess]

This is very much a WIP:

• It doesn't render at all on Safari when running pnpm storybook — the "chunks" served up by the proxy return 404's. It works fine on Firefox and Chrome on macOS.
• The automatic on* handlers for basic interactive testing of actions in the UI has been replaced by a much more cumbersome system where you have to, at the very least, write stub functions for every action on every component. This is going to be quite a bit of work for us. I've started this work in this PR, but there is much left to be done. It sounds like this change has been made with an eye towards more robust testing of actions in Storybook, which is unfortunate for us, as we have no intention of using Storybook for this purpose. The only testing we do in Storybook is a quick automated visual diff when we upgrade libraries etc. I don't think it's a suitable environment for anything more robust; at the very least, I don't think we want to increase our dependency on it.

I'm posting this PR with the expectation that I may find time to work on it here and there, and maybe eventually finish the upgrade, but it seems just as likely that we'll ditch it, as Storybook seems to be moving in a direction we don't particularly care to follow.

[dhess]

The Safari rendering issue appears to be fixed with the latest version of Storybook, and it turns out that the old automatically-generated on* handler schema still works — it's just deprecated. Therefore, I think this is now in good enough shape to merge. We can migrate to new Storybook 8 features etc. at our leisure, rather than all at once in a mega-PR.