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/l10n/app_localizations_en.dart

@@ -144,6 +144,18 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get croatian => 'Croatian';
 
+  @override
+  String get german => 'German';
+
+  @override
+  String get spanish => 'Spanish';
+
+  @override
+  String get french => 'French';
+
+  @override
+  String get italian => 'Italian';
+
   @override
   String get locationBroadcasting => 'Location Broadcasting';
 
@@ -385,6 +397,16 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get storedPermanently => 'Stored permanently in room';
 
+  @override
+  String drawingsSentToPublicChannel(int count, String plural) {
+    return 'Sent $count map drawing$plural to Public Channel';
+  }
+
+  @override
+  String drawingsSharedToPublicChannel(int success, int total) {
+    return 'Shared $success/$total drawings to Public Channel';
+  }
+
   @override
   String get notConnectedToDevice => 'Not connected to device';
 
@@ -999,6 +1021,9 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get failed => 'Failed';
 
+  @override
+  String get broadcast => 'Broadcast';
+
   @override
   String get sarMarkerFoundPerson => 'Found Person';