feat: update VPS purchase API response structure

[derrickobedgiu1]

Summary

• Updates the VPS virtual machine purchase endpoint to handle the new API response structure
• Creates new VirtualMachineOrder class to encapsulate both order and virtual machine data
• Maintains backward compatibility for all other endpoints

Changes Made

• New Class: Added VirtualMachineOrder data class in src/Data/Vps/VirtualMachineOrder.php
• Updated Method: Modified VirtualMachine::purchase() to return VirtualMachineOrder instead of Order
• Enhanced Testing: Added TestFactory::virtualMachineOrder() method and updated related tests
• Documentation: Updated README examples to show new response structure usage

API Changes Implemented

Based on the June 18, 2025 changelog for POST /api/vps/v1/virtual-machines:

Removed Properties (200 response):

• id, subscription_id, status, currency, subtotal, total, billing_address, created_at, updated_at

Added Properties (200 response):

• order - Contains all billing/order information
• virtual_machine - Contains virtual machine details

Usage Example

// Before
$order = $hostinger->vps()->virtualMachines()->purchase($data);
$order->id; // 2957087
$order->status->value; // completed

// After
$response = $hostinger->vps()->virtualMachines()->purchase($data);
$response->order->id; // 2957087
$response->order->status->value; // completed

$response->virtual_machine->id; // 1268054
$response->virtual_machine->hostname; // my.server.tld

Breaking Changes

None. This change only affects the VPS purchase endpoint and maintains backward compatibility for all other Order-related functionality.