feat: Add comprehensive documentation suite and reorganize project structure

- Created complete documentation in docs/ directory
- Added PROJECT_OVERVIEW.md with feature highlights and getting started guide
- Added ARCHITECTURE.md with system design and technical details
- Added SECURITY.md with comprehensive security implementation guide
- Added DEVELOPMENT.md with development workflows and best practices
- Added DEPLOYMENT.md with production deployment instructions
- Added API.md with complete REST API documentation
- Added CONTRIBUTING.md with contribution guidelines
- Added CHANGELOG.md with version history and migration notes
- Reorganized all documentation files into docs/ directory for better organization
- Updated README.md with proper documentation links and quick navigation
- Enhanced project structure with professional documentation standards

f_scripts/shared/flagicon/flags/4x3/gb-eng.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="480" width="640" version="1" viewBox="0 0 640 480">
+  <path fill="#fff" d="M0 0h640v480H0z"/>
+  <path fill="#ce1124" d="M281.6 0h76.8v480h-76.8z"/>
+  <path fill="#ce1124" d="M0 201.6h640v76.8H0z"/>
+</svg>