Add closed PR trigger for publishing context

Include pull_request.closed in Process-PSModule triggers so merged PR context is available for Publish-Site evaluation.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: MariusStorhaug

.github/workflows/Process-PSModule.yml

@@ -11,6 +11,7 @@ on:
     branches:
       - main
     types:
+      - closed
       - opened
       - reopened
       - synchronize