Add PackageInfoCommand to display package configuration information and support status

src/StaticPHP/Package/Package.php

@@ -138,6 +138,16 @@ abstract class Package
         return $this->stages;
     }
 
+    /**
+     * Get the list of OS families that have a registered build function (via #[BuildFor]).
+     *
+     * @return string[] e.g. ['Linux', 'Darwin']
+     */
+    public function getBuildForOSList(): array
+    {
+        return array_keys($this->build_functions);
+    }
+
     /**
      * Check if the package has a specific stage defined.
      *