ci(pages_cleanup): add cron and manual trigger

.github/workflows/pages_cleanup.yml

@@ -1,9 +1,9 @@
 name: GitHub Pages Cleanup
 
 on:
-  push:
+  schedule:
-    branches:
+    - cron: '0 0 * * 0'
-      - gh-pages
+  workflow_dispatch:
 
 permissions:
   contents: write
@@ -14,6 +14,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          ref: gh-pages
 
       - name: Delete directories older than 1 year
         run: |