Modify workflow to always run build, deploy only on main

Co-authored-by: rajbos <6085745+rajbos@users.noreply.github.com>

Author: Copilot

.github/workflows/deploy-to-pages.yml

@@ -1,9 +1,11 @@
 name: Deploy to GitHub Pages
 
 on:
-  # Runs on pushes targeting the default branch
+  # Runs on pushes to any branch to validate build
   push:
-    branches: ["main"]
+  
+  # Runs on pull requests to validate build  
+  pull_request:
 
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch:
@@ -143,6 +145,8 @@ jobs:
 
   # Deployment job
   deploy:
+    # Only deploy on main branch
+    if: github.ref == 'refs/heads/main'
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}