fix: correct acme.sh webroot path for HTTP-01 validation

acme.sh --webroot expects the document root and appends
/.well-known/acme-challenge/<token> itself. Passing challengeDir
caused double nesting, resulting in 404 from Let's Encrypt.

Author: jorikfon

Lib/GetSslMain.php

@@ -388,7 +388,9 @@ public function startGetCertSsl(bool $asynchronously = true): PBXApiResult
             $cmd = $envExports . $cmd;
         } else {
             // HTTP-01 challenge via webroot
-            $webroot = $this->dirs['challengeDir'];
+            // acme.sh appends /.well-known/acme-challenge/<token> to webroot,
+            // so pass the document root (confDir), not the challenge dir
+            $webroot = $this->dirs['confDir'];
             $cmd .= " --webroot " . escapeshellarg($webroot);
         }