chore(ci): Also rebuild Pages on main pushes for content edits

Adds push: [main] alongside workflow_dispatch so edits to README.md, _config.yml, _layouts, or the CHANGELOG.md template publish without a manual dispatch. The chain step in release-tag.yml still runs after release publish to guarantee the new release is in site.github.releases by the time Pages rebuilds — concurrency: cancel-in-progress: false serialises the two runs.

Adds an if: github.ref == 'refs/heads/main' guard on the deploy job so workflow_dispatch from a non-main branch builds for verification but doesn't deploy.

.github/workflows/pages.yml

@@ -1,6 +1,8 @@
 name: Deploy GitHub Pages
 
 on:
+  push:
+    branches: [ main ]
   workflow_dispatch:
 
 permissions:
@@ -42,6 +44,7 @@ jobs:
   deploy:
     name: Deploy to GitHub Pages
     needs: build
+    if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-22.04
     permissions:
       pages: write