Update Danger to validate the standard pull request template

[ulises-jeremias]

Summary

Update Danger so it validates the standard NaNLABS public pull request template.

Context

The repository is adopting a standard PR template with Summary, Type of change, How was this tested?, and Checklist sections. Danger should validate those sections consistently while keeping contributor feedback public-safe.

Acceptance Criteria

• Danger warns when required PR template sections are missing.
• Danger keeps failing human-authored PRs that do not reference a real issue.
• Placeholder references such as #ISSUE do not satisfy the issue-reference requirement.
• Bot, app, release, and version automation PRs remain exempt where appropriate.
• Danger messages are actionable and public-safe.

Suggested Validation

• Run the Danger TypeScript check.
• Validate the GitHub Actions workflow YAML.
• Open or update a test PR description to confirm warnings are understandable.