Add localization support for German, Spanish, French, and Italian

- Updated localization files for French, Croatian, Italian, Slovenian to include translations for German, Spanish, French, and Italian.
- Added new methods for handling drawing messages sent to the public channel in multiple languages.
- Enhanced the Contact model to identify public channels using a dedicated method.
- Implemented echo detection for public channel messages, including tracking and reporting of echoes.
- Updated BLE response handling to support echo detection and tracking of sent messages.
- Modified UI components to reflect new localization strings and echo statuses.

lib/providers/app_provider.dart

@@ -208,6 +208,12 @@ class AppProvider with ChangeNotifier {
       messagesProvider.markMessageDelivered(ackCode, roundTripTimeMs);
     };
 
+    // When an echo is detected for a public channel message (PUSH_CODE_LOG_RX_DATA matched)
+    connectionProvider.onMessageEchoDetected = (messageId, echoCount, snrRaw, rssiDbm) {
+      debugPrint('🔊 [AppProvider] Echo detected - Message: $messageId, Count: $echoCount');
+      messagesProvider.handleMessageEcho(messageId, echoCount, snrRaw, rssiDbm);
+    };
+
     // Wire up MessagesProvider's sendMessageCallback for retry logic
     messagesProvider.sendMessageCallback = ({
       required contactPublicKey,
@@ -284,7 +290,7 @@ class AppProvider with ChangeNotifier {
     try {
       // Get all room contacts (excluding Public Channel)
       final rooms = contactsProvider.rooms
-          .where((room) => room.advName != 'Public Channel')
+          .where((room) => !room.isPublicChannel)
           .toList();
 
       if (rooms.isEmpty) {

lib/providers/connection_provider.dart

@@ -133,6 +133,8 @@ class ConnectionProvider with ChangeNotifier {
   Function(String messageId, int expectedAckTag, int suggestedTimeoutMs)?
   onMessageSent;
   Function(int ackCode, int roundTripTimeMs)? onMessageDelivered;
+  Function(String messageId, int echoCount, int snrRaw, int rssiDbm)?
+  onMessageEchoDetected;
   Function(Uint8List publicKeyPrefix, Uint8List statusData)? onStatusResponse;
 
   // Track pending send operations for auto-recovery
@@ -381,6 +383,13 @@ class ConnectionProvider with ChangeNotifier {
       onMessageDelivered?.call(ackCode, roundTripTimeMs);
     };
 
+    _bleService.onMessageEchoDetected = (messageId, echoCount, snrRaw, rssiDbm) {
+      print(
+        '🔊 [Provider] Echo detected - Message: $messageId, Count: $echoCount',
+      );
+      onMessageEchoDetected?.call(messageId, echoCount, snrRaw, rssiDbm);
+    };
+
     _bleService.onStatusResponse = (publicKeyPrefix, statusData) {
       print('📥 [Provider] Status response received from node');
       print(
@@ -774,8 +783,16 @@ class ConnectionProvider with ChangeNotifier {
     }
 
     try {
+      debugPrint('📨 [ConnectionProvider] sendChannelMessage called:');
+      debugPrint('  Channel: $channelIdx');
+      debugPrint('  Text: $text');
+      debugPrint('  MessageID: $messageId');
+
       await _bleService.sendChannelMessage(channelIdx: channelIdx, text: text);
 
+      debugPrint('✅ [ConnectionProvider] BLE send completed');
+      debugPrint('  Checking messageId: ${messageId != null ? "Present ($messageId)" : "NULL"}');
+
       // Channel messages are ephemeral (not persisted) - mark as "sent" immediately
       // They don't have ACK/TAG mechanism like direct messages
       if (messageId != null) {
@@ -783,6 +800,12 @@ class ConnectionProvider with ChangeNotifier {
         print('  Message ID: $messageId');
         print('  onMessageSent callback exists: ${onMessageSent != null}');
 
+        // Track for echo detection
+        // The BLE handler will capture the packet via LOG_RX_DATA and associate it
+        debugPrint('  Calling trackSentChannelMessage...');
+        _bleService.trackSentChannelMessage(messageId);
+        debugPrint('  trackSentChannelMessage completed');
+
         // Small delay to ensure the message is in the MessagesProvider list
         // before we try to mark it as sent
         await Future.delayed(const Duration(milliseconds: 50));

lib/providers/messages_provider.dart

@@ -602,6 +602,36 @@ class MessagesProvider with ChangeNotifier {
     }
   }
 
+  /// Handle echo detection for public channel messages
+  void handleMessageEcho(String messageId, int echoCount, int snrRaw, int rssiDbm) {
+    print('🔊 [MessagesProvider] handleMessageEcho called');
+    print('  Message ID: $messageId');
+    print('  Echo count: $echoCount');
+    print('  SNR: ${(snrRaw.toSigned(8) / 4.0).toStringAsFixed(2)} dB');
+    print('  RSSI: ${rssiDbm.toSigned(8)} dBm');
+
+    // Find the message
+    final index = _messages.indexWhere((m) => m.id == messageId);
+    if (index != -1) {
+      final message = _messages[index];
+      print('  ✅ Found message: ${message.text.substring(0, message.text.length > 30 ? 30 : message.text.length)}...');
+
+      // Update echo count
+      final updatedMessage = message.copyWith(
+        echoCount: echoCount,
+        firstEchoAt: message.firstEchoAt ?? DateTime.now(),
+      );
+      _messages[index] = updatedMessage;
+
+      print('  Updated echo count to: $echoCount');
+      _persistMessages();
+      notifyListeners();
+      print('  ✅ Echo update complete, UI notified');
+    } else {
+      print('  ⚠️ Message not found in messages list');
+    }
+  }
+
   /// Update message status to delivered with RTT
   void markMessageDelivered(int ackCode, int roundTripTimeMs) {
     print('🔍 [MessagesProvider] markMessageDelivered called with ACK: $ackCode, RTT: ${roundTripTimeMs}ms');