docs: audit and format documentation for public release

[ncurrie3]

Public Release Documentation Audit and Formatting

This PR prepares the Stellar Engine documentation for public release by adding required authorization documents and fixing Markdown formatting issues

Changes Included

• New Documentation: Added the following authorization and best practice guides to the docs/ directory:
  • docs/ddg.md (Deployment Design Guide)
  • docs/path-to-authorization.md
  • docs/scc-deployment-guide.md
  • docs/security-best-practices.md
  • docs/tdd.md (Technical Design Document)
• Formatting Fixes:
  • Corrected <variable> formatting in docs/ddg.md where variables were previously unescaped and hidden in Markdown previews.
  • Fixed incorrect bolding and mismatched escaped asterisks (\*) in docs/security-best-practices.md and docs/path-to-authorization.md.
  • Cleaned up lingering TODO items in blueprints/il5/bq-project/README.md and fast/stages-aw/0-bootstrap/README.md.