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_modules/m_frontend/m_cron/disk_usage.php

@@ -0,0 +1,45 @@
+<?php
+/*******************************************************************************************************************
+| Software Name        : EasyStream
+| Software Description : High End YouTube Clone Script with Videos, Shorts, Streams, Images, Audio, Documents, Blogs
+| Software Author      : (c) Sami Ahmed
+|*******************************************************************************************************************
+|
+|*******************************************************************************************************************
+| This source file is subject to the EasyStream Proprietary License Agreement.
+| 
+| By using this software, you acknowledge having read this Agreement and agree to be bound thereby.
+|*******************************************************************************************************************
+| Copyright (c) 2025 Sami Ahmed. All rights reserved.
+|*******************************************************************************************************************/
+
+define('_ISVALID', true);
+
+$main_dir = realpath(dirname(__FILE__) . '/../../../');
+
+set_time_limit(0);
+set_include_path($main_dir);
+
+include_once 'f_core/config.core.php';
+include_once $class_language->setLanguageFile('frontend', 'language.email.notif');
+
+$cfg[] = $class_database->getConfigurations('backend_email');
+
+$bytes     = disk_free_space("/");
+$si_prefix = array('B', 'KB', 'MB', 'GB', 'TB', 'EB', 'ZB', 'YB');
+$base      = 1024;
+$class     = min((int) log($bytes, $base), count($si_prefix) - 1);
+
+$data = sprintf('%1.2f', $bytes / pow($base, $class)) . ' ' . $si_prefix[$class];
+$free = sprintf('%1.2f', $bytes / pow($base, $class));
+
+if ($si_prefix[$class] == 'GB') {
+    if ($free < 5) {
+        VNotify::queInit('disk_usage', array($cfg['backend_email']), $data);
+    }
+}
+if ($si_prefix[$class] == 'MB') {
+    if ($free < 900) {
+        VNotify::queInit('disk_usage', array($cfg['backend_email']), $data);
+    }
+}