Feat/welcome

[imotai]

---

PR-Codex overview

This PR focuses on adding a welcome workflow to greet users for opening their first issue or pull request.

Detailed summary

• Added a welcome.yml file in the .github/workflows directory.
• The workflow is triggered when a pull request is opened or closed, or when an issue is opened.
• The workflow runs on the latest Ubuntu environment.
• The workflow uses the wow-actions/welcome@v1 action.
• Added messages for first issue, first pull request, and first merged pull request.
• Added a star message to encourage users to star the repository.

✨ Ask PR-Codex anything about this PR by commenting with /codex {your question}