AWS prescriptive-guidance documentation change
Summary
Renamed file from welcome.md to introduction.md and updated internal links. Removed document history date, changed author attribution format, and standardized capitalization in migration steps list.
Security assessment
Changes are administrative (file rename/link updates) and editorial (capitalization consistency). No security vulnerabilities, configurations, or features are mentioned or modified. The migration guidance remains focused on general cloud migration steps without security-specific content.