Initial commit: X-Server Mobile enterprise tool system

- Frontend: React 18 + TypeScript + Vite + Ant Design Mobile
- Backend: PHP 8.5 + Webman 2.x + MySQL + Redis
- i18n support: Chinese, English, Russian, Spanish, French
- Approval workflow engine
- Docker development environment
- Feishu integration

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/config/database.php

@@ -0,0 +1,24 @@
+<?php
+
+return [
+    'default' => 'mysql',
+    'connections' => [
+        'mysql' => [
+            'driver' => 'mysql',
+            'host' => getenv('DB_HOST') ?: 'mysql',
+            'port' => getenv('DB_PORT') ?: 3306,
+            'database' => getenv('DB_DATABASE') ?: 'x_server_mobile',
+            'username' => getenv('DB_USERNAME') ?: 'root',
+            'password' => getenv('DB_PASSWORD') ?: '123456',
+            'unix_socket' => getenv('DB_SOCKET') ?: '',
+            'charset' => 'utf8mb4',
+            'collation' => 'utf8mb4_unicode_ci',
+            'prefix' => '',
+            'strict' => true,
+            'engine' => null,
+            'options' => [
+                \PDO::ATTR_TIMEOUT => 5,
+            ],
+        ],
+    ],
+];