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_de.arb

@@ -1356,12 +1356,12 @@
       }
     }
   },
-  "repeater_neighbours": "Nachbarn",
-  "repeater_neighboursSubtitle": "Anzahl der Hop-Nachbarn anzeigen.",
+  "repeater_neighbors": "Nachbarn",
+  "repeater_neighborsSubtitle": "Anzahl der Hop-Nachbarn anzeigen.",
   "neighbors_receivedData": "Empfangene Nachbarsdaten",
   "neighbors_requestTimedOut": "Anfrage durch Timeout fehlgeschlagen.",
   "neighbors_errorLoading": "Fehler beim Laden der Nachbarn: {error}",
-  "neighbors_repeatersNeighbours": "Nachbarn",
+  "neighbors_repeatersNeighbors": "Nachbarn",
   "neighbors_noData": "Keine Nachbarsdaten verfügbar.",
   "channels_joinPrivateChannel": "Treten Sie einem privaten Kanal bei",
   "channels_joinPrivateChannelDesc": "Manuelle Eingabe eines geheimen Schlüssels.",