feat: Implement user authentication and database migration system

- Refactored AuthService to use UserRepository for user authentication.
- Added .env file for environment configuration.
- Created migration system with Migrator and ConnectionFactory classes.
- Added database migration files for creating users table.
- Implemented settings controller for managing database migrations.
- Developed user repository for user data handling.
- Created users controller for user management interface.
- Added frontend standards and migration documentation.
- Introduced reusable UI components and jQuery alerts module.

config/database.php

@@ -0,0 +1,14 @@
+<?php
+declare(strict_types=1);
+
+use App\Core\Support\Env;
+
+return [
+    'driver' => Env::get('DB_CONNECTION', 'mysql'),
+    'host' => Env::get('DB_HOST', '127.0.0.1'),
+    'port' => (int) Env::get('DB_PORT', '3306'),
+    'database' => Env::get('DB_DATABASE', 'orderpro'),
+    'username' => Env::get('DB_USERNAME', 'root'),
+    'password' => Env::get('DB_PASSWORD', ''),
+    'charset' => Env::get('DB_CHARSET', 'utf8mb4'),
+];