add platforminfo helper

lib/connector/meshcore_connector.dart

@@ -30,6 +30,7 @@ import '../storage/message_store.dart';
 import '../storage/unread_store.dart';
 import '../utils/app_logger.dart';
 import '../utils/battery_utils.dart';
+import '../utils/platform_info.dart';
 import 'meshcore_protocol.dart';
 
 class MeshCoreUuids {
@@ -693,8 +694,7 @@ class MeshCoreConnector extends ChangeNotifier {
     await _scanSubscription?.cancel();
 
     // On iOS/macOS, wait for Bluetooth to be powered on before scanning
-    if (defaultTargetPlatform == TargetPlatform.iOS ||
-        defaultTargetPlatform == TargetPlatform.macOS) {
+    if (PlatformInfo.isIOS || PlatformInfo.isMacOS) {
       // Wait for adapter state to be powered on
       final adapterState = await FlutterBluePlus.adapterState.first;
       if (adapterState != BluetoothAdapterState.on) {

lib/screens/scanner_screen.dart

@@ -1,7 +1,6 @@
 import 'dart:async';
-import 'dart:io' show Platform;
-
 import 'package:flutter/material.dart';
+import '../utils/platform_info.dart';
 import 'package:flutter_blue_plus/flutter_blue_plus.dart';
 import 'package:provider/provider.dart';
 
@@ -265,7 +264,7 @@ class _ScannerScreenState extends State<ScannerScreen> {
               ],
             ),
           ),
-          if (Platform.isAndroid)
+          if (PlatformInfo.isAndroid)
             TextButton(
               onPressed: () => FlutterBluePlus.turnOn(),
               child: Text(context.l10n.scanner_enableBluetooth),

lib/services/background_service.dart

@@ -1,12 +1,11 @@
-import 'dart:io';
-
+import '../utils/platform_info.dart';
 import 'package:flutter_foreground_task/flutter_foreground_task.dart';
 
 class BackgroundService {
   bool _initialized = false;
 
   Future<void> initialize() async {
-    if (!Platform.isAndroid || _initialized) return;
+    if (!PlatformInfo.isAndroid || _initialized) return;
     FlutterForegroundTask.init(
       androidNotificationOptions: AndroidNotificationOptions(
         channelId: 'meshcore_background',
@@ -29,7 +28,7 @@ class BackgroundService {
   }
 
   Future<void> start() async {
-    if (!Platform.isAndroid) return;
+    if (!PlatformInfo.isAndroid) return;
     if (!_initialized) {
       await initialize();
     }
@@ -43,7 +42,7 @@ class BackgroundService {
   }
 
   Future<void> stop() async {
-    if (!Platform.isAndroid) return;
+    if (!PlatformInfo.isAndroid) return;
     final running = await FlutterForegroundTask.isRunningService;
     if (!running) return;
     await FlutterForegroundTask.stopService();

lib/utils/gpx_export.dart

@@ -4,6 +4,7 @@ import 'package:meshcore_open/connector/meshcore_connector.dart';
 import 'package:meshcore_open/connector/meshcore_protocol.dart';
 import 'package:path_provider/path_provider.dart';
 import 'dart:io';
+import '../utils/platform_info.dart';
 
 import 'package:share_plus/share_plus.dart';
 
@@ -109,6 +110,10 @@ class GpxExport {
     String shareText,
     String subject,
   ) async {
+    if (PlatformInfo.isWeb) {
+      debugPrint("GPX export is not supported on Web.");
+      return gpxExportNotAvailable;
+    }
     if (_contacts.isEmpty) {
       debugPrint("No repeaters to export – nothing to share.");
       return gpxExportNoContacts;

lib/utils/platform_info.dart

@@ -0,0 +1,32 @@
+import 'package:flutter/foundation.dart';
+import 'dart:io' show Platform;
+
+/// Utility class to safely check the current platform across web and native.
+///
+/// Using `Platform` from `dart:io` directly on Web causes a crash.
+/// This class handles the `kIsWeb` check first to avoid those crashes.
+class PlatformInfo {
+  /// Whether the app is running in a web browser.
+  static bool get isWeb => kIsWeb;
+
+  /// Whether the app is running on Android.
+  static bool get isAndroid => !kIsWeb && Platform.isAndroid;
+
+  /// Whether the app is running on iOS.
+  static bool get isIOS => !kIsWeb && Platform.isIOS;
+
+  /// Whether the app is running on macOS.
+  static bool get isMacOS => !kIsWeb && Platform.isMacOS;
+
+  /// Whether the app is running on Windows.
+  static bool get isWindows => !kIsWeb && Platform.isWindows;
+
+  /// Whether the app is running on Linux.
+  static bool get isLinux => !kIsWeb && Platform.isLinux;
+
+  /// Whether the app is running on a mobile platform (Android or iOS).
+  static bool get isMobile => isAndroid || isIOS;
+
+  /// Whether the app is running on a desktop platform (macOS, Windows, or Linux).
+  static bool get isDesktop => isMacOS || isWindows || isLinux;
+}

lib/widgets/repeater_login_dialog.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import '../utils/platform_info.dart';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/foundation.dart';
@@ -326,8 +327,7 @@ class _RepeaterLoginDialogState extends State<RepeaterLoginDialog> {
                     },
                     onSubmitted: (_) => _handleLogin(),
                     autofocus:
-                        !(defaultTargetPlatform == TargetPlatform.android ||
-                            defaultTargetPlatform == TargetPlatform.iOS) &&
+                        !PlatformInfo.isMobile &&
                         _passwordController.text.isEmpty,
                   ),
                   const SizedBox(height: 12),

lib/widgets/room_login_dialog.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import '../utils/platform_info.dart';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/foundation.dart';
@@ -274,8 +275,7 @@ class _RoomLoginDialogState extends State<RoomLoginDialog> {
                     ),
                     onSubmitted: (_) => _handleLogin(),
                     autofocus:
-                        !(defaultTargetPlatform == TargetPlatform.android ||
-                            defaultTargetPlatform == TargetPlatform.iOS) &&
+                        !PlatformInfo.isMobile &&
                         _passwordController.text.isEmpty,
                   ),
                   const SizedBox(height: 12),