feat(ci): add duplicate issue detection workflow

[mahek2016]

Closes #267

📝 Description

This PR introduces an automated GitHub Actions workflow to detect potential duplicate issues when a new issue is opened.

The workflow:

• Triggers on new issue creation
• Scans existing open issues
• Compares titles to detect potential duplicates
• Posts a comment suggesting similar issues
• Does NOT auto-close issues (maintainers retain control)

This helps reduce duplicate issue noise and improves contributor experience.
This implementation is modular and can be extended later to use fuzzy matching or similarity scoring for better duplicate detection.
The workflow only posts a suggestion comment and does not automatically close, label, or modify issues.

🔧 Changes Made

• Added new GitHub Actions workflow: .github/workflows/duplicate-issue-check.yml
• Implemented duplicate title scanning using actions/github-script
• Added automated comment logic for similar issues
• Ensured workflow is lightweight and requires no external dependencies

📷 Screenshots or Visual Changes (if applicable)

N/A – CI workflow enhancement (no UI changes)

🤝 Collaboration

N/A

✅ Checklist

• I have read the contributing guidelines.
• I have manually tested the workflow by opening a sample issue.
• I have added necessary documentation (if applicable).
• Any dependent changes have been merged and published in downstream modules.