skill: add hipaa-assistant

[lralic4]

Problem

Founders building HIPAA-compliant GenAI apps on AWS can't discover the sample-hipaa-assistant tool unless they're already searching GitHub.

Solution

Adds a skill that surfaces the HIPAA assistant tool in founders' IDEs when they ask about HIPAA compliance scanning for GenAI workloads.

Closes #133

Type of Change

• New plugin/power/tool

Team Folder

• Other: solution-architecture/

Checklist

• I have read the CONTRIBUTING.md guidelines
• My changes do not include hardcoded secrets, credentials, or internal-only content
• I have run mise run build locally and it passes
• I have updated documentation if needed
• My changes are scoped to my team's folder only

[rsmets]

Thanks for the contribution! I don't have an issue with this is arrangement but I do worry it opens up future PRs that just reference already existing gh repos. Maybe that's actually a fantastic pattern 🤔

[lralic4]

thanks! wasn't sure what the best approach was