Add build function check for current OS and update validation logic

src/StaticPHP/Package/Package.php

@@ -127,6 +127,14 @@ abstract class Package
         return false;
     }
 
+    /**
+     * Check if the package has a build function for the current OS.
+     */
+    public function hasBuildFunctionForCurrentOS(): bool
+    {
+        return isset($this->build_functions[PHP_OS_FAMILY]);
+    }
+
     /**
      * Get the name of the package.
      */

src/StaticPHP/Registry/PackageLoader.php

@@ -306,7 +306,9 @@ class PackageLoader
                         }
                     }
                     // check stage exists
-                    if (!$pkg->hasStage($stage_name)) {
+                    // Skip validation if the package has no build function for current OS
+                    // (e.g., libedit has BeforeStage for 'build' but only BuildFor('Darwin'/'Linux'))
+                    if (!$pkg->hasStage($stage_name) && $pkg->hasBuildFunctionForCurrentOS()) {
                         throw new RegistryException("Package stage [{$stage_name}] is not registered in package [{$package_name}].");
                     }
                 }