chore: import upstream snapshot with attribution

tests/fixtures/sample_php_container.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Providers;
+
+class PaymentGateway {}
+class StripeGateway {}
+class CashierGateway {}
+
+class AppServiceProvider
+{
+    public function register(): void
+    {
+        $this->app->bind(PaymentGateway::class, StripeGateway::class);
+        $this->app->singleton(CashierGateway::class, StripeGateway::class);
+    }
+}