Add website CI build with artifacts for pull requests

.github/workflows/website.yaml

@@ -2,9 +2,11 @@
 name: Build and deploy OFT website using GitHub Pages
 
 on:
-  # Runs on pushes targeting the default branch
+  # Runs on pushes targeting main or gh-pages branch (deploy on gh-pages only)
   push:
-    branches: ["gh-pages"]
+    branches: ["gh-pages", "main"]
+  pull_request:
+    types: [opened, reopened, synchronize]
 
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch:
@@ -41,7 +43,14 @@ jobs:
       - name: Create build dir
         run: mkdir build_docs
 
-      - name: Configure OFT documentation
+      - name: Configure OFT documentation (nightly)
+        if: github.ref != 'ref/head/gh-pages'
+        shell: bash
+        working-directory: build_docs
+        run: cmake -DOFT_BUILD_DOCS:BOOL=ON -DOFT_DOCS_ONLY:BOOL=ON -DOFT_PACKAGE_NIGHTLY:BOOL=ON ../src
+
+      - name: Configure OFT documentation (deploy)
+        if: github.ref == 'ref/head/gh-pages'
         shell: bash
         working-directory: build_docs
         run: cmake -DOFT_BUILD_DOCS:BOOL=ON -DOFT_DOCS_ONLY:BOOL=ON -DOFT_PACKAGE_NIGHTLY:BOOL=OFF ../src
@@ -61,12 +70,22 @@ jobs:
           chmod -c -R +rX "_site/" | while read line; do
             echo "::warning title=Invalid file permissions automatically fixed::$line"
           done
+
+      - name: Upload actions artifact
+        if: github.ref != 'ref/head/gh-pages'
+        uses: actions/upload-artifact@v4
+        with:
+          name: pull_${{ github.event.pull_request.number }}-website
+          path: _site/
+          overwrite: true
 
-      - name: Upload artifact
+      - name: Upload pages artifact
+        if: github.ref == 'ref/head/gh-pages'
         uses: actions/upload-pages-artifact@v3
 
   # Deployment job
   deploy:
+    if: github.ref == 'ref/head/gh-pages'
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}