Add demo script for PECL usage in billing service

Introduce a new demo script `05-pecl.php` under the `demo` directory. This script sets up an Aspect-Oriented Programming (AOP) configuration and demonstrates error handling within a billing service.

demo/05-pecl.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ray\Aop\Demo;
+
+use Ray\Aop\Aspect;
+use Ray\Aop\Matcher;
+use RuntimeException;
+
+use const PHP_EOL;
+
+require __DIR__ . '/bootstrap.php';
+
+$aspect = new Aspect(__DIR__ . '/tmp');
+$aspect->bind(
+    (new Matcher())->any(),
+    new IsContainsMatcher('charge'),
+    [new WeekendBlocker()]
+);
+$aspect->weave(__DIR__. '/src');
+
+try {
+    $billingService = new RealBillingService();
+    echo $billingService->chargeOrder();
+} catch (RuntimeException $e) {
+    echo $e->getMessage() . PHP_EOL;
+    exit(1);
+}