AWS prescriptive-guidance documentation change
Summary
Renamed file from welcome.md to introduction.md, updated internal links/anchors, removed document history date, simplified author affiliation formatting, and made minor markdown syntax adjustments
Security assessment
Changes are primarily structural/documentation maintenance (renaming, link updates, formatting). The RLS (Row-Level Security) mention remains unchanged in substance - only formatting was modified with extra asterisks. No new security content added or vulnerabilities addressed.