feat: extension runtime and provider improvements

lib/utils/extension_auth_launcher.dart

@@ -0,0 +1,42 @@
+import 'package:spotiflac_android/services/platform_bridge.dart';
+import 'package:spotiflac_android/utils/logger.dart';
+import 'package:url_launcher/url_launcher.dart';
+
+final _log = AppLogger('ExtensionAuthLauncher');
+
+bool isExtensionVerificationRequired(Object error) {
+  final message = error.toString().toLowerCase();
+  return message.contains('verify_required') ||
+      message.contains('verification_required') ||
+      message.contains('needsverification') ||
+      message.contains('needs verification');
+}
+
+Future<void> openPendingExtensionVerification(String extensionId) async {
+  final normalizedExtensionId = extensionId.trim();
+  if (normalizedExtensionId.isEmpty) return;
+
+  try {
+    final pending = await PlatformBridge.getExtensionPendingAuth(
+      normalizedExtensionId,
+    );
+    final authUrl = pending?['auth_url']?.toString().trim() ?? '';
+    if (authUrl.isEmpty) return;
+
+    final uri = Uri.tryParse(authUrl);
+    if (uri == null) return;
+
+    final launched = await launchUrl(uri, mode: LaunchMode.externalApplication);
+    if (launched) {
+      _log.i('Opened verification challenge for $normalizedExtensionId');
+    } else {
+      _log.w(
+        'Could not open verification challenge for $normalizedExtensionId',
+      );
+    }
+  } catch (e) {
+    _log.w(
+      'Failed to open verification challenge for $normalizedExtensionId: $e',
+    );
+  }
+}