[TEMP][DO NOT MERGE] Trigger pages.yml on the fork branch for validation

Temporarily run the GitHub Pages workflow on the fork to validate the container-based doc build: trigger on push to this branch, drop the apache/spark job guard, and skip the Pages configure/deploy steps on the fork. To be reverted before merge.

Author: zhengruifeng

.github/workflows/pages.yml

@@ -23,6 +23,8 @@ on:
   push:
     branches:
       - master
+      # TEMP: validate this workflow on the fork, remove before merge
+      - pages-reuse-doc-image-dev1
 
 concurrency:
   group: 'docs preview'
@@ -44,7 +46,7 @@ jobs:
       RELEASE_VERSION: 'In-Progress'
       LC_ALL: C.UTF-8
       LANG: C.UTF-8
-    if: github.repository == 'apache/spark'
+    # TEMP: job-level repository guard removed to run on the fork, restore before merge
     steps:
       - name: Checkout Spark repository
         uses: actions/checkout@v6
@@ -78,11 +80,15 @@ jobs:
           cd docs
           SKIP_RDOC=1 bundle exec jekyll build
       - name: Setup Pages
+        # TEMP: skip Pages API calls on the fork (Pages not enabled there), remove the if before merge
+        if: github.repository == 'apache/spark'
         uses: actions/configure-pages@v6
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v5
         with:
           path: 'docs/_site'
       - name: Deploy to GitHub Pages
+        # TEMP: skip deployment on the fork, remove the if before merge
+        if: github.repository == 'apache/spark'
         id: deployment
         uses: actions/deploy-pages@v5