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_auth/login.php

@@ -0,0 +1,28 @@
+<?php
+if (!defined('_ISVALID')) define('_ISVALID', true);
+include_once 'f_core/config.core.php';
+
+// Handle login
+if ($_SERVER['REQUEST_METHOD'] === 'POST') {
+    $username = $_POST['username'] ?? '';
+    $password = $_POST['password'] ?? '';
+    
+    if ($username && $password) {
+        $sql = "SELECT * FROM db_accountuser WHERE usr_user = ? AND usr_password = MD5(?) AND usr_active = 1";
+        $user = $class_database->execute($sql, [$username, $password]);
+        
+        if ($user && count($user) > 0) {
+            $_SESSION['usr_id'] = $user[0]['usr_id'];
+            $_SESSION['usr_user'] = $user[0]['usr_user'];
+            $_SESSION['usr_key'] = $user[0]['usr_key'];
+            
+            echo "<script>alert('Login successful! Redirecting...'); window.location.href='/';</script>";
+            exit;
+        } else {
+            $error = 'Invalid credentials';
+        }
+    }
+}
+
+echo $class_smarty->displayPage('frontend', 'tpl_auth_login');
+?>