fix(workflow): add history tracking to prevent duplicate throwback posts

Pass history_variable_name and HISTORY_PAT secret to the reusable
random-blog-post-from-rss workflow to track previously selected posts
and avoid duplicates for 2 years (104 weeks).

Requires: CodingWithCalvin/.github#45

Author: CalvinAllen

.github/workflows/throwback-thursday.yml

@@ -12,6 +12,9 @@ jobs:
     uses: CodingWithCalvin/.github/.github/workflows/random-blog-post-from-rss.yml@main
     with:
       rss_url: 'https://www.codingwithcalvin.net/rss.xml'
+      history_variable_name: 'THROWBACK_HISTORY'
+    secrets:
+      HISTORY_TOKEN: ${{ secrets.HISTORY_PAT }}
 
   post-bluesky:
     needs: select