Fix workflow syncing issue for dev.

Author: Guangzhen-Jin

.github/workflows/sync_main_to_dev.yml

@@ -42,8 +42,10 @@ jobs:
         run: |
           git fetch origin main
           git merge origin/main --no-edit -X ours
-          # Restore dev-only framework files
-          git checkout ORIG_HEAD -- docs/index.md
+          # Restore dev-only files: homepage and all workflow files.
+          # Workflow files are excluded because the GitHub App lacks the
+          # `workflows` permission required to push changes to them.
+          git checkout ORIG_HEAD -- docs/index.md .github/workflows/
           git diff --cached --quiet || git commit -m "Restore dev framework files after main sync"
 
       - name: Push dev