Add PR check workflow

Author: tracpants

.github/workflows/pr-checks.yml

@@ -0,0 +1,55 @@
+name: Pull Request Checks
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  lint-markdown:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the code
+        uses: actions/checkout@v3
+
+      - name: Install Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: '16'
+
+      - name: Install markdownlint
+        run: |
+          npm install -g markdownlint-cli
+
+      - name: Run markdown lint
+        run: |
+          markdownlint "**/*.md"
+
+  spell-check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the code
+        uses: actions/checkout@v3
+
+      - name: Install cspell
+        run: |
+          npm install -g cspell
+
+      - name: Run spell check
+        run: |
+          cspell "**/*.md" || echo "Some spelling errors detected. Review the log for details."
+
+  validate-yaml-front-matter:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the code
+        uses: actions/checkout@v3
+
+      - name: Validate front matter
+        run: |
+          for file in _posts/*.md; do
+            if ! grep -q "title:" "$file" || ! grep -q "date:" "$file"; then
+              echo "Error: Missing required front matter fields in $file"
+              exit 1
+            fi
+          done