docs: add first guide for schema governance series

[sarahxsanders]

Description

adds the first guide for the new "schema governance" guides for graphql.org/learn

includes new guide: review and validate schema changes:

• defining review criteria
• automate validation
• CI/CD integration
• ownership and approval process
• breaking changes
• scaling
• pitfalls

Note

PLEASE DO NOT MERGE, THIS IS THE FIRST IN A THREE GUIDE SERIES

next guides are on:

• naming conventions and design standards: define consistent naming and documentation patterns
• schema ownership and governance: expand on the basics from this guide
• evolve schemas with versioning and tooling

[vercel]

@sarahxsanders is attempting to deploy a commit to the The GraphQL Foundation Team on Vercel.

A member of the Team first needs to authorize it.

[martinbonnin]

@sarahxsanders is this ready? Do you need feedbacks on this?

[sarahxsanders]

@martinbonnin yes this is ready!

[martinbonnin]

Awesome @sarahxsanders ! I'll review now!

@benjie @hasparus Do you have access to Vercel to approve the preview?

[Urigo]

great work, I won't comment here but some of the comments I've made in the other PR but in high level some of them are related here as well

[vercel]

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

Project	Deployment	Actions	Updated (UTC)
graphql-github-io	Error		Apr 23, 2026 9:48am

[benjie]

Vercel is reporting the same issue as CI, which I believe was addressed in the comments above.

info  - Need to disable some ESLint rules? Learn more here: https://nextjs.org/docs/basic-features/eslint#disabling-rules
Failed to compile.
./src/components/learn-aggregator/learn-pages.tsx:13:7
Type error: Property '"review-and-validate-schema-changes"' is missing in type '{ introduction: { description: string; icon: string; section: "getting-started"; }; schema: { description: string; icon: string; section: "getting-started"; }; queries: { description: string; icon: string; section: "getting-started"; }; ... 18 more ...; "debug-errors": { ...; }; }' but required in type 'Record<LearnPagePath, Omit<LearnPageItem, "title" | "href"> | null>'.
  11 | }
  12 |
> 13 | const _items: Record<
     |       ^
  14 |   LearnPagePath,
  15 |   Omit<LearnPageItem, "title" | "href"> | null
  16 | > = {
Next.js build worker exited with code: 1 and signal: null
 ELIFECYCLE  Command failed with exit code 1.
Error: Command "pnpm run build" exited with 1