build: Swapping NPM for PNPM Step 3 of 5

[scotttjob]

Motivations

1. We've long wanted to explore pnpm, and between some of the new features they're rolling out, the fact that Storybook is embracing it fully, and some of our internal packages have as well.
2. This PR Chain is in 5 steps, to make it easier to review.
3. This third PR is making upgrading Storybook 9 -> 10, and integrating Storybook MCP.
4. This PR is not technically required as part of this chain to upgrade to pnpm, but it was the original spark for the work, which is why it's here.
5. If we decide to instead cherry pick these changes against master instead, that's fine with me!

Changes

1. Migrating to Storybook 10 in both repos.
2. Adding Storybook MCP
3. Some changes to get everything building.

Changes can be
tested via Pre-release

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In Atlantis we use Github's built in pull request reviews.

[MichaelParadis]

I don't think you meant to commit this

[MichaelParadis]

Don't think you meant to commit this