Fix findModuleRoot to handle directory paths correctly

Co-authored-by: robertvansteen <14931924+robertvansteen@users.noreply.github.com>

Author: Copilot

src/Rules/RestrictImplicitDependencyUsage.php

@@ -122,7 +122,9 @@ public function isRestrictedClassNameUsage(ClassReflection $classReflection, Sco
 
     private function findModuleRoot(string $file): string
     {
-        $dir = dirname($file);
+        // Start from the file's directory, or the path itself if it's already a directory
+        $dir = is_dir($file) ? $file : dirname($file);
+        
         while ($dir !== '/') {
             if (file_exists($dir . '/composer.json')) {
                 return $dir;