feat(release): add workflow_dispatch to release-pr.yml for manual testing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: richardthe3rd

.github/workflows/release-pr.yml

@@ -5,6 +5,7 @@ on:
     branches: [main]
   schedule:
     - cron: '0 6 * * *'
+  workflow_dispatch:
 
 permissions:
   contents: write