Maintenance: Replace fast-glob with glob() from node:fs/promises #1495
Description
Proposed change
As of Node.js v24, the glob API is stable. It doesn't support all features of fast-glob. Given that there only are few places in the Keystatic monorepo where fast-glob, and since all of them are used for development and testing only, they can all be replaced with the built-in API.
Affected modules:
design-system/primitives/scripts/build.tsdesign-system/primitives/scripts/buildTokens.tspackages/keystatic/test/test-utils.ts
Why make this change
This would primarily reduce the packages to install for development and testing, while also reducing the surface for supply chain attacks.
How to implement glob from node:fs/promises
https://nodejs.org/docs/v24.12.0/api/fs.html#fspromisesglobpattern-options