add windows as target

lib/core/io_open.dart

@@ -0,0 +1,26 @@
+import 'dart:io';
+
+import 'package:flutter/foundation.dart';
+
+/// Opens a folder in the native file explorer.
+/// Returns true if a launch was attempted.
+Future<bool> openFolder(String path) async {
+  if (path.isEmpty) return false;
+  try {
+    if (kIsWeb) return false;
+    if (Platform.isWindows) {
+      await Process.run('explorer', [path]);
+      return true;
+    } else if (Platform.isMacOS) {
+      await Process.run('open', [path]);
+      return true;
+    } else if (Platform.isLinux) {
+      await Process.run('xdg-open', [path]);
+      return true;
+    }
+  } catch (_) {
+    // ignore errors; caller can show a message
+  }
+  return false;
+}
+