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_templates/tpl_frontend/tpl_headchannel_min.tpl

@@ -0,0 +1 @@
+        <link rel="canonical" href="{$main_url}/@{$usr_user}" />{insert name="getProfileImage" assign="profileImage" for="{$usr_id}"}<meta name="author" content="{$main_url}" /><meta name="copyright" content="{$website_shortname}" /><meta name="application-name" content="{$website_shortname}" /><meta name="thumbnail" content="{$profileImage}" /><meta property="og:title" content="{insert name=getPageMeta for="title"}" /><meta property="og:type" content="article" /><meta property="og:image" content="{$profileImage}" /><meta property="og:image:width" content="640" /><meta property="og:image:height" content="360" /><meta property="og:url" content="{$main_url}{$smarty.server.REQUEST_URI}" /><meta property="og:description" content="{insert name=getPageMeta for="description"}" /><meta name="twitter:card" content="summary" /><meta name="twitter:title" content="{insert name=getPageMeta for="title"}" /><meta name="twitter:description" content="{insert name=getPageMeta for="description"}" /><meta name="twitter:image" content="{$profileImage}" /><link rel="image_src" href="{$profileImage}">