Fix pr-review.yml with proper GitHub Actions workflow

[devin-ai-integration]

Summary

The pr-review.yml file previously contained git shell commands instead of a valid GitHub Actions workflow definition, causing it to be ignored by GitHub (resulting in "Checks: 0" on PRs). This PR replaces the invalid content with a proper workflow that automatically posts a welcome comment on new PRs.

The workflow triggers on pull_request events (opened/reopened) and posts a comment containing PR statistics (files changed, lines added/removed) and a review checklist for maintainers.

Review & Testing Checklist for Human

• Verify the YAML syntax is valid (can use a YAML linter or GitHub's workflow editor)
• Check that the template literal indentation in the JavaScript won't cause extra whitespace in the posted comment
• Test by creating a new PR to confirm the workflow triggers and posts the expected comment

Recommended test plan: After merging, create a test PR to verify the workflow runs and posts the welcome comment correctly. Check that the comment formatting looks clean without extra indentation.

Notes

The fetch-depth: 0 in the checkout step may be unnecessary since we're only posting a comment, but it doesn't cause any issues.

Link to Devin run: https://medline.devinenterprise.com/sessions/7d77bf01e9f74760871abfdbc2516613

Requested by: sshankar@medline.com (@sshankarmedline)

[devin-ai-integration]

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[github-actions]

PR Review Checklist

Thank you @devin-ai-integration[bot] for your contribution!

PR Summary:

• Title: Fix pr-review.yml with proper GitHub Actions workflow
• Files changed: 1
• Lines added: 52
• Lines removed: 3

Review Guidelines:

• Code follows the project's coding standards
• Changes are well-documented
• Tests have been added/updated if applicable
• No sensitive information is exposed

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