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/jp.svg

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="480" width="640" version="1" viewBox="0 0 640 480">
+  <defs>
+    <clipPath id="a">
+      <path fill-opacity=".67" d="M-88.001 32h640v480h-640z"/>
+    </clipPath>
+  </defs>
+  <g fill-rule="evenodd" clip-path="url(#a)" transform="translate(88.001 -32)" stroke-width="1pt">
+    <path fill="#fff" d="M-128 32h720v480h-720z"/>
+    <ellipse rx="194.93" ry="194.93" transform="translate(-168.44 8.618) scale(.76554)" cy="344.05" cx="523.08" fill="#d30000"/>
+  </g>
+</svg>