BUILD-8639: Add cursor rules to help with migration

[jayadeep-km-sonarsource]

BUILD-8639: Add cursor rules to help with migration

The md file is supposed to be comprehensive and verbose documentation for AI tools like cursor to help with the documentation. We should keep it up-to-date as needed.

To use this, we can prompt the AI as below

Refer @https://github.com/SonarSource/ci-github-actions/blob/feat/jd/BUILD-8639-cursor-rule-migration/.cursor/cirrus-github-migration.md  and migrate @.cirrus.yml 

If the user is signed into github in Cursor, it will read the guide and do the migration

[sonarqubecloud]

🤖 Pull Request summary

This pull request adds comprehensive documentation for migrating from CirrusCI to GitHub Actions.

• Adds migration guide: Creates detailed 990-line documentation covering migration patterns, security practices, and best practices
• Includes security guidelines: Documents action pinning requirements, secure input handling, and permissions management
• Provides migration templates: Offers complete workflow examples for Maven, Gradle, and Poetry projects with runner selection guidance
• Documents troubleshooting: Covers common issues, vault permissions setup, and testing strategies
• Updates contribution docs: Adds instructions for using AI tools with the migration guide as context

💬 Please send your feedback

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud