Next.js 15 for Hub

[berekuk]

• --turbo is enabled by default in pnpm run dev or turbo run dev; builds are much faster
• Relay transforms work; Worker from squiggle-lang works (took me a while to find the optimal configuration that's compatible both with Next 15 and storybook in components...)
• I had to upgrade next-auth to v5 beta, because it's still not released, but it seems to work fine for email sign-ins; I'll have to check the github flow when we deploy this to production, and in the worse case we'll have to revert
• there's a patch for react-select, described in https://github.com/JedWatson/react-select/issues/5859

This PR is made unrelated to #3450, but implemented on top of it, to simplify the merge. (I hoped #3450 would go in before I'm done with this).

So the right diff to review is this: https://github.com/quantified-uncertainty/squiggle/pull/3452/files/764ace42b2585ecfef93e5abdcaadd4b0068cf57..a53b6fbbbcb09cb1090e839f8d17d942a783817c (most of it is awaits because of https://nextjs.org/blog/next-15#async-request-apis-breaking-change)

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: f84baa10170e5a82dcbe0d36ac66fd6a67aef1b5

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
quri-hub	✅ Ready (Inspect)	Visit Preview	Nov 25, 2024 0:49am
squiggle-website	✅ Ready (Inspect)	Visit Preview	Nov 25, 2024 0:49am

2 Skipped Deployments

| Name | Status | Preview | Updated (UTC) | | :--- | :----- | :------ | :------ | | **quri-ui** | ⬜️ Ignored ([Inspect](https://vercel.com/quantified-uncertainty/quri-ui/6sk4oWY3ZZzZA2TQcWiSzDUL9ELm)) | [Visit Preview](https://quri-ui-git-next-15-quantified-uncertainty.vercel.app) | Nov 25, 2024 0:49am | | **squiggle-components** | ⬜️ Ignored ([Inspect](https://vercel.com/quantified-uncertainty/squiggle-components/5Ls4VPCSdRRt36zceiQvtaCRyR8W)) | [Visit Preview](https://squiggle-components-git-next-15-quantified-uncertainty.vercel.app) | Nov 25, 2024 0:49am |