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/lang/en.php

@@ -0,0 +1,75 @@
+<?php
+
+/**
+ * English translation file
+ */
+return [
+    'app' => [
+        'name' => 'Enterprise Tool System',
+        'title' => 'Enterprise Internal Tool Platform',
+    ],
+    'common' => [
+        'success' => 'Operation successful',
+        'error' => 'Operation failed',
+        'confirm' => 'Confirm',
+        'cancel' => 'Cancel',
+        'submit' => 'Submit',
+        'save' => 'Save',
+        'delete' => 'Delete',
+        'edit' => 'Edit',
+        'search' => 'Search',
+        'refresh' => 'Refresh',
+        'back' => 'Back',
+        'close' => 'Close',
+        'loading' => 'Loading...',
+        'no_data' => 'No data',
+        'operation' => 'Operation',
+        'status' => 'Status',
+        'create_time' => 'Create Time',
+        'update_time' => 'Update Time',
+        'remark' => 'Remark',
+    ],
+    'auth' => [
+        'login_success' => 'Login successful',
+        'login_failed' => 'Login failed',
+        'username_required' => 'Username is required',
+        'password_required' => 'Password is required',
+        'invalid_credentials' => 'Invalid username or password',
+        'token_expired' => 'Session expired, please login again',
+        'unauthorized' => 'Unauthorized, please login first',
+    ],
+    'user' => [
+        'not_found' => 'User not found',
+        'info_updated' => 'Profile updated successfully',
+        'company_switched' => 'Company switched successfully',
+    ],
+    'approval' => [
+        'submit_success' => 'Approval submitted successfully',
+        'approve_success' => 'Approved successfully',
+        'reject_success' => 'Rejected successfully',
+        'cancel_success' => 'Cancelled successfully',
+        'not_found' => 'Approval not found',
+        'cannot_approve' => 'Cannot approve in current status',
+        'cannot_cancel' => 'Cannot cancel in current status',
+        'not_owner' => 'Only the applicant can cancel',
+        'status' => [
+            'pending' => 'Pending',
+            'approved' => 'Approved',
+            'rejected' => 'Rejected',
+            'cancelled' => 'Cancelled',
+        ],
+    ],
+    'business_trip' => [
+        'submit_success' => 'Business trip submitted successfully',
+        'update_success' => 'Business trip updated successfully',
+        'not_found' => 'Business trip not found',
+    ],
+    'error' => [
+        'network_error' => 'Network error, please try again later',
+        'server_error' => 'Server error',
+        'not_found' => 'Page not found',
+        'unknown_error' => 'Unknown error',
+        'params_error' => 'Parameter error',
+        'validation_error' => 'Validation failed',
+    ],
+];