feat(tests): add schema test coverage

* remove json version of schema
* add package-lock.json
* mistakenly removed validate-markdown gh action

reused from OAS/Overlay projects

Author: jeremyfiel

.github/workflows/schema-tests.yaml

@@ -0,0 +1,36 @@
+name: schema-tests
+
+# Author: @MikeRalphson / runs @jdesrosiers tests
+# Issue: https://github.com/OAI/OpenAPI-Specification/pull/2489
+
+#
+# This workflow runs the npm test script to validate passing and failing
+# testcases for the metaschemas
+#
+
+# run this on push to any branch and creation of pull-requests
+on: 
+  push: {}
+  pull_request: {}
+  workflow_dispatch: {}
+
+jobs:
+  test:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4 # checkout repo content
+      with:
+        fetch-depth: 0
+
+    - uses: actions/setup-node@v4 # setup Node.js
+      with:
+        node-version: '20.x'
+
+    - name: Install dependencies from main
+      run: |
+        # git checkout remotes/origin/main -- package.json package-lock.json #TODO: uncomment with subsequent PR
+        npm ci
+    - name: Run tests
+      run: npm test

.gitignore

@@ -9,3 +9,4 @@ node_modules/
 deploy/
 history
 Gemfile.lock
+coverage/