fix(storybook): migrate Storybook v8 -> v10, repairing the Pages deploy

[Ndevu12]

Fixes the broken GitHub Pages deploy and closes Dependabot alert #46 (uuid).

The deploy has been failing on every push

Deploy to GitHub Pages has failed 6 runs in a row, going back to before any of this weeks security work. The Build storybook step dies, and because it fails, every later step — including the deploy itself — is skipped:

Build nextjs-demo        success
Build storybook          failure
Assemble deployment dir  skipped
Upload Pages artifact    skipped
Deploy to GitHub Pages   skipped

So Pages has not published in days. (This is also what looked like "tests being cancelled" — nothing is cancelled; steps after the failure are skipped, which renders greyed-out.)

Root cause

package.json declared @storybook/react-vite at ^10.3.4 while storybook / @storybook/core stayed at ^8.6.0. Storybook 8 core cannot load a v10 builder, so preset resolution died:

Error: Cannot find module ..._@storybook/builder-vite/dist/index.js

I confirmed this reproduces on a clean main worktree, so it is genuinely pre-existing and not a side effect of the dependency work.

Changes

Package	Change
storybook	^8.6.0 → ^10.5.5
@storybook/addon-a11y	^8.6.0 → ^10.5.5
@storybook/react-vite	^10.3.4 → ^10.5.5
@storybook/addon-essentials	removed — folded into core in v9+
@storybook/blocks	removed — folded into core in v9+, and was declared but never imported anywhere

Config and stories now import from the framework package (@storybook/react-vite) instead of the renderer (@storybook/react) — the latter was never a declared dependency and only resolved transitively, which is its own latent breakage.

Closes #46 (uuid, medium) properly

@storybook/addon-actions@8.6.18 was the only thing pulling uuid@^9.0.0, and it was pinned to a major we could not reach. Storybook 9+ dropped the uuid dependency entirely, so after this migration uuid is absent from the lockfile:

grep -c "uuid@npm:" yarn.lock   ->  0

That is a real removal, not a resolutions override — which is exactly why I left it unfixed in #106 rather than forcing a pin.

Verification

• yarn build-storybook — Storybook build completed successfully (this is the previously failing step)
• yarn build · 286 unit tests · yarn typecheck · yarn lint · yarn format:check — all pass