refactor(demos): improve variable box, scope, and type annotation demos
style(demos): update visual styles and animations for better UX
docs(browser-as-os): restructure content with tables and practical examples
feat(demos): add new TypeScript and runtime environment demos
- Move standalone AI-related files into 8-artificial-intelligence directory
- Move development tools content into 2-development-tools directory
- Move server/backend content into 4-server-and-backend directory
- Create new index files for each section
- Update .gitignore to exclude old backup directories
- Update theme imports for new component locations