chore: added schemas folder (W-23365673)

[jfeingold35]

What does this PR do?

Adds a schemas folder.

What issues does this PR fix or reference?

@W-23365673@

[jhefferman-sfdc]

CI: rebase to pick up the NUT fix

The two red checks here — nuts (ubuntu-latest) and nuts (windows-latest) — are not caused by this PR. They're the pre-existing post-release API-version drift tracked by W-23400737, where scratch orgs provision on a newer API version than the plugin bundles a dev server for, so the dev server exits before printing the preview URL and every browser test times out.

That fix has now merged to main (#676). This branch (d/W-23365673) predates it, so it's still running the old NUT harness.

To get CI green: rebase (or merge main in) and re-push:

git fetch origin
git rebase origin/main      # or: git merge origin/main
git push --force-with-lease  # (plain git push if you merged instead of rebased)

For reference, everything owned by this PR is already passing: unit tests (Node 22 + 24), yarn-lockfile-check, pr-validation, and schema:compare (test:json-schema) — so once the NUT fix is in, the branch should be fully green.

[jfeingold35]

@jhefferman-sfdc , I've rebased this branch off of main.