Add contact settings and discovery features

- Implemented contact settings in localization files for Swedish, Ukrainian, and Chinese.
- Added new DiscoveryContact model to handle discovered contacts.
- Created DiscoveryScreen to display discovered contacts with filtering and sorting options.
- Integrated contact discovery storage to persist discovered contacts.
- Updated settings screen to include options for automatic contact addition.
- Enhanced app bar and list filter widgets for better user experience.
- Fixed variable naming inconsistencies in contact model.

lib/models/contact.dart

@@ -183,7 +183,7 @@ class Contact {
             )
           : Uint8List(0);
       final name = readCString(data, contactNameOffset, maxNameSize);
-      final lastmod = readUint32LE(data, contactLastmodOffset);
+      final lastmod = readUint32LE(data, contactLastModOffset);
 
       double? lat, lon;
       final latRaw = readInt32LE(data, contactLatOffset);