feat: implement local http server in desktop platforms for oauth2

packages/better_networking/lib/utils/platform_utils.dart

@@ -0,0 +1,19 @@
+import 'dart:io';
+import 'package:flutter/foundation.dart';
+
+/// Platform detection utilities for the better_networking package.
+class PlatformUtils {
+  /// Returns true if running on desktop platforms (macOS, Windows, Linux).
+  static bool get isDesktop =>
+      !kIsWeb && (Platform.isMacOS || Platform.isWindows || Platform.isLinux);
+
+  /// Returns true if running on mobile platforms (iOS, Android).
+  static bool get isMobile => !kIsWeb && (Platform.isIOS || Platform.isAndroid);
+
+  /// Returns true if running on web.
+  static bool get isWeb => kIsWeb;
+
+  /// Returns true if OAuth should use localhost callback server.
+  /// This is true for desktop platforms.
+  static bool get shouldUseLocalhostCallback => isDesktop;
+}