Support running the workflow on push to main #84

Context

The Process-PSModule workflow currently triggers on pull request events. Some workflows need to run when code is pushed directly to main (e.g., after a merge or manual push).

Request

The workflow should support running on push to main by using the List pull requests associated with a commit API to determine the associated PR context.

Acceptance criteria

• The workflow can be triggered on push to main
• PR context (labels, title, body) is retrieved from the commit's associated PR
• Release type and other PR-derived logic works correctly from the push event

Technical decisions

API approach: Use the List pull requests associated with a commit endpoint to map the merge commit back to its source PR.

Implementation plan

• Add push event trigger for the main branch to the workflow
• Implement commit-to-PR mapping using the GitHub API
• Extract PR metadata (labels, title, body) from the associated PR
• Feed the PR metadata into the existing release/publish logic
• Test with merged PRs and direct pushes