fix pages workflow

.github/workflows/pages.yml

@@ -6,6 +6,11 @@ on:
     paths:
       - "docs/**"
       - ".github/workflows/pages.yml"
+  pull_request:
+    branches: [main]
+    paths:
+      - "docs/**"
+      - ".github/workflows/pages.yml"
 
 permissions:
   contents: read
@@ -19,13 +24,34 @@ concurrency:
 jobs:
   build:
     runs-on: ubuntu-latest
+    outputs:
+      pages_configured: ${{ steps.pages_site.outputs.configured }}
     steps:
       - uses: actions/checkout@v6
 
+      - name: Detect Pages site
+        id: pages_site
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          if [ "${{ github.event_name }}" != "push" ]; then
+            echo "configured=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          if curl -fsSL \
+            -H "Authorization: Bearer ${GH_TOKEN}" \
+            -H "Accept: application/vnd.github+json" \
+            "https://api.github.com/repos/${GITHUB_REPOSITORY}/pages" >/dev/null; then
+            echo "configured=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "configured=false" >> "$GITHUB_OUTPUT"
+            echo "::notice::GitHub Pages is not configured for this repository; skipping artifact upload and deploy."
+          fi
+
       - name: Setup Pages
+        if: github.event_name == 'push' && steps.pages_site.outputs.configured == 'true'
         uses: actions/configure-pages@v6
-        with:
-          enablement: true
 
       - name: Build with Jekyll
         uses: actions/jekyll-build-pages@v1
@@ -34,9 +60,11 @@ jobs:
           destination: ./_site
 
       - name: Upload artifact
+        if: github.event_name == 'push' && steps.pages_site.outputs.configured == 'true'
         uses: actions/upload-pages-artifact@v4
 
   deploy:
+    if: github.event_name == 'push' && needs.build.outputs.pages_configured == 'true'
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}