Update PayPal references and tests

app/Services/LemonSqueezy/LemonSqueezyClient.php

@@ -7,6 +7,7 @@ use Illuminate\Http\Client\Factory as HttpFactory;
 use Illuminate\Http\Client\PendingRequest;
 use Illuminate\Http\Client\RequestException;
 use Illuminate\Support\Arr;
+use Illuminate\Support\Str;
 
 class LemonSqueezyClient
 {
@@ -68,7 +69,7 @@ class LemonSqueezyClient
             throw new LemonSqueezyException('Lemon Squeezy API key is not configured.');
         }
 
-        $baseUrl = rtrim((string) config('lemonsqueezy.base_url'), '/');
+        $baseUrl = $this->normalizeBaseUrl((string) config('lemonsqueezy.base_url'));
 
         return $this->http
             ->baseUrl($baseUrl)
@@ -81,4 +82,30 @@ class LemonSqueezyClient
             ->acceptJson()
             ->asJson();
     }
+
+    protected function normalizeBaseUrl(string $baseUrl): string
+    {
+        $baseUrl = trim($baseUrl);
+
+        if ($baseUrl === '') {
+            $baseUrl = 'https://api.lemonsqueezy.com/v1';
+        }
+
+        if (! Str::startsWith($baseUrl, ['http://', 'https://'])) {
+            $baseUrl = 'https://api.lemonsqueezy.com/'.ltrim($baseUrl, '/');
+        }
+
+        $parsedHost = parse_url($baseUrl, PHP_URL_HOST);
+        if (! is_string($parsedHost) || $parsedHost === '' || ! Str::endsWith($parsedHost, 'lemonsqueezy.com')) {
+            $baseUrl = 'https://api.lemonsqueezy.com/v1';
+        }
+
+        $baseUrl = rtrim($baseUrl, '/');
+
+        if (! Str::endsWith($baseUrl, '/v1')) {
+            $baseUrl .= '/v1';
+        }
+
+        return $baseUrl;
+    }
 }