Refactor localization keys for "neighbors" terminology across multiple languages

- Updated localization keys from "neighbours" to "neighbors" in the following files:
  - app_localizations_bg.dart
  - app_localizations_de.dart
  - app_localizations_en.dart
  - app_localizations_es.dart
  - app_localizations_fr.dart
  - app_localizations_it.dart
  - app_localizations_nl.dart
  - app_localizations_pl.dart
  - app_localizations_pt.dart
  - app_localizations_ru.dart
  - app_localizations_sk.dart
  - app_localizations_sl.dart
  - app_localizations_sv.dart
  - app_localizations_uk.dart
  - app_localizations_zh.dart
- Updated corresponding ARB files to reflect the changes in keys.
- Renamed the NeighboursScreen to NeighborsScreen in the chat and repeater hub screens for consistency.

lib/l10n/app_localizations_en.dart

@@ -1654,10 +1654,10 @@ class AppLocalizationsEn extends AppLocalizations {
   String get repeater_cliSubtitle => 'Send commands to the repeater';
 
   @override
-  String get repeater_neighbours => 'Neighbors';
+  String get repeater_neighbors => 'Neighbors';
 
   @override
-  String get repeater_neighboursSubtitle => 'View zero hop neighbors.';
+  String get repeater_neighborsSubtitle => 'View zero hop neighbors.';
 
   @override
   String get repeater_settings => 'Settings';
@@ -2333,10 +2333,10 @@ class AppLocalizationsEn extends AppLocalizations {
   }
 
   @override
-  String get neighbors_receivedData => 'Received Neighbours Data';
+  String get neighbors_receivedData => 'Received Neighbors Data';
 
   @override
-  String get neighbors_requestTimedOut => 'Neighbours request timed out.';
+  String get neighbors_requestTimedOut => 'Neighbors request timed out.';
 
   @override
   String neighbors_errorLoading(String error) {
@@ -2344,10 +2344,10 @@ class AppLocalizationsEn extends AppLocalizations {
   }
 
   @override
-  String get neighbors_repeatersNeighbours => 'Repeaters Neighbours';
+  String get neighbors_repeatersNeighbors => 'Repeaters Neighbors';
 
   @override
-  String get neighbors_noData => 'No neighbours data available.';
+  String get neighbors_noData => 'No neighbors data available.';
 
   @override
   String neighbors_unknownContact(String pubkey) {