added Groq and openAI APIs

- Added functionality to load and restore the last companion's scope on app startup.
- Implemented caching mechanisms for contacts, channels, and messages related to the current companion.
- Updated UI to reflect connection status, including disabling message input when disconnected.
- Introduced new dialog prompts to inform users when they need to connect to a companion for accessing features.
- Refactored navigation logic to improve user experience when disconnected, directing users to the scanner screen.
- Added localization strings for new companion connection prompts in multiple languages.

lib/connector/meshcore_connector.dart

@@ -40,6 +40,7 @@ import '../storage/contact_discovery_store.dart';
 import '../storage/contact_settings_store.dart';
 import '../storage/contact_store.dart';
 import '../storage/message_store.dart';
+import '../storage/prefs_manager.dart';
 import '../storage/unread_store.dart';
 import '../utils/app_logger.dart';
 import '../utils/battery_utils.dart';
@@ -124,6 +125,8 @@ class MeshCoreRadioStateSnapshot {
 class MeshCoreConnector extends ChangeNotifier {
   // Message windowing to limit memory usage
   static const int _messageWindowSize = 200;
+  static const String _lastCompanionPublicKeyPref =
+      'last_companion_public_key_hex';
 
   MeshCoreConnectionState _state = MeshCoreConnectionState.disconnected;
   BluetoothDevice? _device;
@@ -476,6 +479,9 @@ class MeshCoreConnector extends ChangeNotifier {
   }
 
   List<Message> getMessages(Contact contact) {
+    if (!_loadedConversationKeys.contains(contact.publicKeyHex)) {
+      unawaited(_loadMessagesForContact(contact.publicKeyHex));
+    }
     return _conversations[contact.publicKeyHex] ?? [];
   }
 
@@ -653,7 +659,14 @@ class MeshCoreConnector extends ChangeNotifier {
   }
 
   Future<void> loadCachedChannels() async {
-    _cachedChannels = await _channelStore.loadChannels();
+    final loaded = await _channelStore.loadChannels();
+    _cachedChannels = loaded;
+    if (_channels.isEmpty && loaded.isNotEmpty) {
+      _channels
+        ..clear()
+        ..addAll(loaded);
+      notifyListeners();
+    }
   }
 
   void setActiveContact(String? contactKeyHex) {
@@ -913,6 +926,69 @@ class MeshCoreConnector extends ChangeNotifier {
     }
   }
 
+  Future<void> loadAllCachedDataForCurrentCompanion() async {
+    await loadContactCache();
+    await _loadDiscoveredContactCache();
+    await loadChannelSettings();
+    await loadCachedChannels();
+    await loadAllChannelMessages();
+    await loadUnreadState();
+  }
+
+  Future<void> restoreLastCompanionScope() async {
+    final prefs = PrefsManager.instance;
+    final lastCompanionPublicKeyHex = prefs.getString(
+      _lastCompanionPublicKeyPref,
+    );
+    if (lastCompanionPublicKeyHex == null ||
+        lastCompanionPublicKeyHex.trim().isEmpty) {
+      return;
+    }
+    _setScopedStorePublicKey(lastCompanionPublicKeyHex);
+  }
+
+  Future<void> loadDiscoveredContactCache() => _loadDiscoveredContactCache();
+
+  void _setScopedStorePublicKey(String publicKeyHex) {
+    _channelMessageStore.setPublicKeyHex = publicKeyHex;
+    _messageStore.setPublicKeyHex = publicKeyHex;
+    _channelOrderStore.setPublicKeyHex = publicKeyHex;
+    _channelSettingsStore.setPublicKeyHex = publicKeyHex;
+    _contactSettingsStore.setPublicKeyHex = publicKeyHex;
+    _contactStore.setPublicKeyHex = publicKeyHex;
+    _channelStore.setPublicKeyHex = publicKeyHex;
+    _unreadStore.setPublicKeyHex = publicKeyHex;
+  }
+
+  void _clearCachedCompanionData() {
+    _contacts.clear();
+    _discoveredContacts.clear();
+    _conversations.clear();
+    _loadedConversationKeys.clear();
+    _channelMessages.clear();
+    _cachedChannels.clear();
+    _knownContactKeys.clear();
+    _contactUnreadCount.clear();
+    _unreadStateLoaded = false;
+    notifyListeners();
+  }
+
+  Future<void> _persistLastCompanionScope() async {
+    final keyHex = selfPublicKeyHex;
+    if (keyHex.isEmpty) return;
+    final prefs = PrefsManager.instance;
+    await prefs.setString(_lastCompanionPublicKeyPref, keyHex);
+  }
+
+  Future<void> _reloadOfflineCachesForLastCompanion() async {
+    if (_state != MeshCoreConnectionState.disconnected) {
+      return;
+    }
+    await restoreLastCompanionScope();
+    await loadContactCache();
+    await _loadDiscoveredContactCache();
+  }
+
   Future<void> _loadDiscoveredContactCache() async {
     final cached = await _discoveryContactStore.loadContacts();
     _discoveredContacts
@@ -1450,6 +1526,7 @@ class MeshCoreConnector extends ChangeNotifier {
     _cancelReconnectTimer();
     _manualDisconnect = false;
     _resetConnectionHandshakeState();
+    _clearCachedCompanionData();
     _activeTransport = MeshCoreTransportType.usb;
     _setState(MeshCoreConnectionState.connecting);
 
@@ -1531,6 +1608,7 @@ class MeshCoreConnector extends ChangeNotifier {
     _cancelReconnectTimer();
     _manualDisconnect = false;
     _resetConnectionHandshakeState();
+    _clearCachedCompanionData();
     _activeTransport = MeshCoreTransportType.tcp;
     _setState(MeshCoreConnectionState.connecting);
 
@@ -1665,6 +1743,7 @@ class MeshCoreConnector extends ChangeNotifier {
     _activeTransport = MeshCoreTransportType.bluetooth;
 
     await stopScan();
+    _clearCachedCompanionData();
     _setState(MeshCoreConnectionState.connecting);
     _device = device;
     _deviceId = device.remoteId.toString();
@@ -2416,6 +2495,7 @@ class MeshCoreConnector extends ChangeNotifier {
       'Disconnect complete transport=$transportLabel manual=$manual',
       tag: 'Connection',
     );
+    unawaited(_reloadOfflineCachesForLastCompanion());
     if (!manual && transportAtDisconnect == MeshCoreTransportType.bluetooth) {
       _scheduleReconnect();
     }
@@ -3796,26 +3876,12 @@ class MeshCoreConnector extends ChangeNotifier {
       return;
     }
 
-    //set all the stores' public key so they can load the correct data
+    // Set scoped stores to this companion and remember it for next launch.
-    _channelMessageStore.setPublicKeyHex = selfPublicKeyHex;
+    _setScopedStorePublicKey(selfPublicKeyHex);
-    _messageStore.setPublicKeyHex = selfPublicKeyHex;
+    unawaited(_persistLastCompanionScope());
-    _channelOrderStore.setPublicKeyHex = selfPublicKeyHex;
-    _channelSettingsStore.setPublicKeyHex = selfPublicKeyHex;
-    _contactSettingsStore.setPublicKeyHex = selfPublicKeyHex;
-    _contactStore.setPublicKeyHex = selfPublicKeyHex;
-    _channelStore.setPublicKeyHex = selfPublicKeyHex;
-    _unreadStore.setPublicKeyHex = selfPublicKeyHex;
 
-    // Now that we have self info, we can load all the persisted data for this node
+    // Now that we have self info, we can load all the persisted data for this node.
-    _loadChannelOrder();
+    unawaited(loadAllCachedDataForCurrentCompanion());
-    loadContactCache();
-    loadChannelSettings();
-    loadCachedChannels();
-
-    // Load persisted channel messages
-    loadAllChannelMessages();
-    loadUnreadState();
-    _loadDiscoveredContactCache();
 
     _awaitingSelfInfo = false;
     _selfInfoRetryTimer?.cancel();

lib/l10n/app_bg.arb

@@ -2311,5 +2311,6 @@
   "settings_companionDebugLogSubtitle": "Команди, отговори и сурови данни за протоколите BLE/TCP/USB",
   "chat_newMessages": "Нови съобщения",
   "settings_companionDebugLog": "Лог за отстраняване на грешки (за съпътстваща програма)",
-  "repeater_chanUtil": "Използване на канала"
+  "repeater_chanUtil": "Използване на канала",
+  "contact_connectCompanion": "Свържете се с придружител, за да получите достъп до функциите на ретранслатора и сървъра за стаи."
 }

lib/l10n/app_de.arb

@@ -2339,5 +2339,6 @@
   "chat_newMessages": "Neue Nachrichten",
   "settings_companionDebugLog": "Debug-Protokoll für die Begleitsoftware",
   "settings_companionDebugLogSubtitle": "BLE/TCP/USB-Befehle, Antworten und Rohdaten",
-  "repeater_chanUtil": "Nutzung des Kanals"
+  "repeater_chanUtil": "Nutzung des Kanals",
+  "contact_connectCompanion": "Verbinden Sie sich mit einem Companion, um auf die Funktionen des Repeaters und des Raumservers zuzugreifen."
 }

lib/l10n/app_en.arb

@@ -2366,5 +2366,6 @@
   "contact_typeRepeater": "Repeater",
   "contact_typeRoom": "Room",
   "contact_typeSensor": "Sensor",
-  "contact_typeUnknown": "Unknown"
+  "contact_typeUnknown": "Unknown",
+  "contact_connectCompanion": "Connect to a companion to access repeater and room server features."
 }

lib/l10n/app_es.arb

@@ -2339,5 +2339,6 @@
   "chat_newMessages": "Nuevos mensajes",
   "settings_companionDebugLogSubtitle": "Comandos, respuestas y datos brutos para protocolos BLE/TCP/USB",
   "chat_markAsUnread": "Marcar como no leído",
-  "repeater_chanUtil": "Utilización del canal"
+  "repeater_chanUtil": "Utilización del canal",
+  "contact_connectCompanion": "Conéctate a un compañero para acceder a las funciones de repetidor y servidor de sala."
 }

lib/l10n/app_fr.arb

@@ -2318,5 +2318,6 @@
   "chat_markAsUnread": "Signaler comme non lu",
   "chat_newMessages": "Nouveaux messages",
   "settings_companionDebugLogSubtitle": "Commandes, réponses et données brutes pour les protocoles BLE/TCP/USB",
-  "repeater_chanUtil": "Utilisation du canal"
+  "repeater_chanUtil": "Utilisation du canal",
+  "contact_connectCompanion": "Connectez-vous à un compagnon pour accéder aux fonctionnalités de répéteur et de serveur de salle."
 }

lib/l10n/app_hu.arb

@@ -2349,5 +2349,6 @@
   "chat_newMessages": "Új üzenetek",
   "settings_companionDebugLog": "Párhuzamos hibakeresési napló",
   "settings_companionDebugLogSubtitle": "BLE/TCP/USB parancsok, válaszok és alapvető adatok",
-  "repeater_chanUtil": "Csatorna-használat"
+  "repeater_chanUtil": "Csatorna-használat",
+  "contact_connectCompanion": "Csatlakozzon egy kísérőhöz a ismétlő és szobaszerver funkciók eléréséhez."
 }

lib/l10n/app_it.arb

@@ -2311,5 +2311,6 @@
   "settings_companionDebugLog": "Registro di debug per il supporto",
   "chat_newMessages": "Nuovi messaggi",
   "chat_markAsUnread": "Segna come non letto",
-  "repeater_chanUtil": "Utilizzo del canale"
+  "repeater_chanUtil": "Utilizzo del canale",
+  "contact_connectCompanion": "Connettiti a un dispositivo companion per accedere alle funzionalità di ripetitore e server stanza."
 }

lib/l10n/app_ja.arb

@@ -2349,5 +2349,6 @@
   "settings_companionDebugLog": "同伴デバッグログ",
   "chat_newMessages": "新しいメッセージ",
   "chat_markAsUnread": "未読としてマークする",
-  "repeater_chanUtil": "チャンネルの利用状況"
+  "repeater_chanUtil": "チャンネルの利用状況",
+  "contact_connectCompanion": "コネクトしてリピーターとルームサーバー機能にアクセス"
 }

lib/l10n/app_ko.arb

@@ -2349,5 +2349,6 @@
   "chat_newMessages": "새로운 메시지",
   "settings_companionDebugLogSubtitle": "BLE/TCP/USB 명령어, 응답 및 원시 데이터",
   "chat_markAsUnread": "미리 읽지 않음으로 표시",
-  "repeater_chanUtil": "채널 활용도"
+  "repeater_chanUtil": "채널 활용도",
+  "contact_connectCompanion": "리피터 및 룸 서버 기능에 액세스하려면 컴패니언에 연결하세요."
 }

lib/l10n/app_localizations.dart

@@ -7335,6 +7335,12 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Unknown'**
   String get contact_typeUnknown;
+
+  /// No description provided for @contact_connectCompanion.
+  ///
+  /// In en, this message translates to:
+  /// **'Connect to a companion to access repeater and room server features.'**
+  String get contact_connectCompanion;
 }
 
 class _AppLocalizationsDelegate

lib/l10n/app_localizations_bg.dart

@@ -4288,4 +4288,8 @@ class AppLocalizationsBg extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Свържете се с придружител, за да получите достъп до функциите на ретранслатора и сървъра за стаи.';
 }

lib/l10n/app_localizations_de.dart

@@ -4305,4 +4305,8 @@ class AppLocalizationsDe extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Verbinden Sie sich mit einem Companion, um auf die Funktionen des Repeaters und des Raumservers zuzugreifen.';
 }

lib/l10n/app_localizations_en.dart

@@ -4210,4 +4210,8 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Connect to a companion to access repeater and room server features.';
 }

lib/l10n/app_localizations_es.dart

@@ -4292,4 +4292,8 @@ class AppLocalizationsEs extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Conéctate a un compañero para acceder a las funciones de repetidor y servidor de sala.';
 }

lib/l10n/app_localizations_fr.dart

@@ -4321,4 +4321,8 @@ class AppLocalizationsFr extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Connectez-vous à un compagnon pour accéder aux fonctionnalités de répéteur et de serveur de salle.';
 }

lib/l10n/app_localizations_hu.dart

@@ -4309,4 +4309,8 @@ class AppLocalizationsHu extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Csatlakozzon egy kísérőhöz a ismétlő és szobaszerver funkciók eléréséhez.';
 }

lib/l10n/app_localizations_it.dart

@@ -4297,4 +4297,8 @@ class AppLocalizationsIt extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Connettiti a un dispositivo companion per accedere alle funzionalità di ripetitore e server stanza.';
 }

lib/l10n/app_localizations_ja.dart

@@ -4063,4 +4063,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion => 'コネクトしてリピーターとルームサーバー機能にアクセス';
 }

lib/l10n/app_localizations_ko.dart

@@ -4064,4 +4064,7 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion => '리피터 및 룸 서버 기능에 액세스하려면 컴패니언에 연결하세요.';
 }

lib/l10n/app_localizations_nl.dart

@@ -4273,4 +4273,8 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Maak verbinding met een companion om repeater- en kamerserverfuncties te gebruiken.';
 }

lib/l10n/app_localizations_pl.dart

@@ -4309,4 +4309,8 @@ class AppLocalizationsPl extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Połącz się z towarzyszem, aby uzyskać dostęp do funkcji powtarzacza i serwera pokoi.';
 }

lib/l10n/app_localizations_pt.dart

@@ -4285,4 +4285,8 @@ class AppLocalizationsPt extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Conecte-se a um dispositivo companion para acessar as funcionalidades de repetidor e servidor de salas.';
 }

lib/l10n/app_localizations_ru.dart

@@ -4303,4 +4303,8 @@ class AppLocalizationsRu extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Неизвестно';
+
+  @override
+  String get contact_connectCompanion =>
+      'Подключитесь к компаньону, чтобы получить доступ к функциям ретранслятора и сервера комнат.';
 }

lib/l10n/app_localizations_sk.dart

@@ -4269,4 +4269,8 @@ class AppLocalizationsSk extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Pripojte sa k sprievodcovi a získajte prístup k funkciám opakovača a serveru miestností.';
 }

lib/l10n/app_localizations_sl.dart

@@ -4267,4 +4267,8 @@ class AppLocalizationsSl extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Povežite se s spremljevalnikom za dostop do funkcij ponavljalnika in strežnika sob.';
 }

lib/l10n/app_localizations_sv.dart

@@ -4241,4 +4241,8 @@ class AppLocalizationsSv extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion =>
+      'Anslut till en sällskapstjänst för att komma åt upprepning och rumsserverfunktioner.';
 }

lib/l10n/app_localizations_uk.dart

@@ -4304,4 +4304,8 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Невідомо';
+
+  @override
+  String get contact_connectCompanion =>
+      'Підключіться до супутнього пристрою, щоб отримати доступ до функцій ретранслятора та сервера кімнат.';
 }

lib/l10n/app_localizations_zh.dart

@@ -3938,4 +3938,7 @@ class AppLocalizationsZh extends AppLocalizations {
 
   @override
   String get contact_typeUnknown => 'Unknown';
+
+  @override
+  String get contact_connectCompanion => '连接伴机以访问中继器和房间服务器功能。';
 }

lib/l10n/app_nl.arb

@@ -2311,5 +2311,6 @@
   "chat_newMessages": "Nieuwe berichten",
   "chat_markAsUnread": "Markeer als ongelezen",
   "settings_companionDebugLogSubtitle": "BLE/TCP/USB commando's, antwoorden en ruwe data",
-  "repeater_chanUtil": "Gebruik van het kanaal"
+  "repeater_chanUtil": "Gebruik van het kanaal",
+  "contact_connectCompanion": "Maak verbinding met een companion om repeater- en kamerserverfuncties te gebruiken."
 }

lib/l10n/app_pl.arb

@@ -2349,5 +2349,6 @@
   "settings_companionDebugLogSubtitle": "Polecenia, odpowiedzi i surowe dane związane z protokołami BLE/TCP/USB",
   "chat_markAsUnread": "Oznacz jako nieprzeczytane",
   "settings_companionDebugLog": "Log debugowania (dla pomocy w rozwiązywaniu problemów)",
-  "repeater_chanUtil": "Wykorzystanie kanału"
+  "repeater_chanUtil": "Wykorzystanie kanału",
+  "contact_connectCompanion": "Połącz się z towarzyszem, aby uzyskać dostęp do funkcji powtarzacza i serwera pokoi."
 }

lib/l10n/app_pt.arb

@@ -2311,5 +2311,6 @@
   "settings_companionDebugLogSubtitle": "Comandos, respostas e dados brutos para protocolos BLE/TCP/USB",
   "chat_markAsUnread": "Marcar como não lido",
   "chat_newMessages": "Novas mensagens",
-  "repeater_chanUtil": "Utilização do canal"
+  "repeater_chanUtil": "Utilização do canal",
+  "contact_connectCompanion": "Conecte-se a um dispositivo companion para acessar as funcionalidades de repetidor e servidor de salas."
 }

lib/l10n/app_ru.arb

@@ -1614,5 +1614,6 @@
   "repeater_cliHelpStatsCore": "(Только для серийного оборудования) Отображает основные статистические данные прошивки.",
   "settings_companionDebugLogSubtitle": "Команды, ответы и необработанные данные, используемые для протоколов BLE, TCP и USB.",
   "repeater_chanUtil": "Использование канала",
-  "settings_companionDebugLog": "Журнал отладки (для сопутствующего приложения)"
+  "settings_companionDebugLog": "Журнал отладки (для сопутствующего приложения)",
+  "contact_connectCompanion": "Подключитесь к компаньону, чтобы получить доступ к функциям ретранслятора и сервера комнат."
 }

lib/l10n/app_sk.arb

@@ -2311,5 +2311,6 @@
   "settings_companionDebugLogSubtitle": "Príkazy, odpovede a surové dáta pre protokoly BLE/TCP/USB",
   "settings_companionDebugLog": "Logovanie pre ladenie (sprievodný log)",
   "chat_newMessages": "Nové správy",
-  "repeater_chanUtil": "Využitie kanálu"
+  "repeater_chanUtil": "Využitie kanálu",
+  "contact_connectCompanion": "Pripojte sa k sprievodcovi a získajte prístup k funkciám opakovača a serveru miestností."
 }

lib/l10n/app_sl.arb

@@ -2311,5 +2311,6 @@
   "chat_markAsUnread": "Označiti kot neneobdelano",
   "chat_newMessages": "Nove novice",
   "settings_companionDebugLogSubtitle": "Navodila, odgovori in surova podatka za BLE/TCP/USB.",
-  "repeater_chanUtil": "Uporaba kanala"
+  "repeater_chanUtil": "Uporaba kanala",
+  "contact_connectCompanion": "Povežite se s spremljevalnikom za dostop do funkcij ponavljalnika in strežnika sob."
 }

lib/l10n/app_sv.arb

@@ -2311,5 +2311,6 @@
   "settings_companionDebugLog": "Följande felsökningslogg",
   "chat_newMessages": "Nya meddelanden",
   "settings_companionDebugLogSubtitle": "BLE/TCP/USB-kommandon, svar och rådata",
-  "repeater_chanUtil": "Användning av kanal"
+  "repeater_chanUtil": "Användning av kanal",
+  "contact_connectCompanion": "Anslut till en sällskapstjänst för att komma åt upprepning och rumsserverfunktioner."
 }

lib/l10n/app_uk.arb

@@ -2291,5 +2291,6 @@
   "settings_companionDebugLogSubtitle": "Команди, відповіді та необроблена інформація для протоколів BLE/TCP/USB",
   "chat_newMessages": "Нові повідомлення",
   "chat_markAsUnread": "Позначити як непрочитане",
-  "repeater_chanUtil": "Використання каналу"
+  "repeater_chanUtil": "Використання каналу",
+  "contact_connectCompanion": "Підключіться до супутнього пристрою, щоб отримати доступ до функцій ретранслятора та сервера кімнат."
 }

lib/l10n/app_zh.arb

@@ -2316,5 +2316,6 @@
   "settings_companionDebugLog": "调试日志",
   "chat_newMessages": "新的消息",
   "settings_companionDebugLogSubtitle": "BLE/TCP/USB 协议、响应和原始数据",
-  "repeater_chanUtil": "频道利用率"
+  "repeater_chanUtil": "频道利用率",
+  "contact_connectCompanion": "连接伴机以访问中继器和房间服务器功能。"
 }

lib/main.dart

@@ -5,10 +5,10 @@ import 'l10n/app_localizations.dart';
 import 'package:provider/provider.dart';
 
 import 'screens/chrome_required_screen.dart';
+import 'screens/contacts_screen.dart';
 import 'utils/platform_info.dart';
 
 import 'connector/meshcore_connector.dart';
-import 'screens/scanner_screen.dart';
 import 'services/storage_service.dart';
 import 'services/message_retry_service.dart';
 import 'services/path_history_service.dart';
@@ -81,13 +81,8 @@ void main() async {
     timeoutPredictionService: timeoutPredictionService,
   );
 
-  await connector.loadContactCache();
+  await connector.restoreLastCompanionScope();
-  await connector.loadChannelSettings();
+  await connector.loadAllCachedDataForCurrentCompanion();
-  await connector.loadCachedChannels();
-
-  // Load persisted channel messages
-  await connector.loadAllChannelMessages();
-  await connector.loadUnreadState();
 
   runApp(
     MeshCoreApp(
@@ -218,7 +213,7 @@ class MeshCoreApp extends StatelessWidget {
             },
             home: (PlatformInfo.isWeb && !PlatformInfo.isChrome)
                 ? const ChromeRequiredScreen()
-                : const ScannerScreen(),
+                : const ContactsScreen(),
           );
         },
       ),

lib/models/path_history.dart

@@ -3,6 +3,7 @@ class PathRecord {
   final int tripTimeMs;
   final DateTime? timestamp;
   final bool wasFloodDiscovery;
+  final int byteCount;
   final List<int> pathBytes;
   final int successCount;
   final int failureCount;
@@ -17,6 +18,7 @@ class PathRecord {
     required this.successCount,
     required this.failureCount,
     this.routeWeight = 1.0,
+    this.byteCount = 0,
   });
 
   String get displayText =>

lib/screens/channel_chat_screen.dart

@@ -1057,6 +1057,9 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
 
   Widget _buildMessageComposer() {
     final connector = context.watch<MeshCoreConnector>();
+    if (!connector.isConnected) {
+      return const SizedBox.shrink();
+    }
     final maxBytes = maxChannelMessageBytes(connector.selfName);
     final settings = context.watch<AppSettingsService>().settings;
     return Column(
@@ -1208,6 +1211,9 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
   }
 
   Future<void> _sendMessage() async {
+    final connector = context.read<MeshCoreConnector>();
+    if (!connector.isConnected) return;
+
     final text = _textController.text.trim();
     if (text.isEmpty) return;
 
@@ -1222,7 +1228,6 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
     }
     _lastChannelSendAt = now;
 
-    final connector = context.read<MeshCoreConnector>();
     final settings = context.read<AppSettingsService>().settings;
     final translationService = context.read<TranslationService>();
 

lib/screens/channels_screen.dart

@@ -17,7 +17,6 @@ import '../models/channel.dart';
 import '../models/community.dart';
 import '../storage/community_store.dart';
 import '../utils/dialog_utils.dart';
-import '../utils/disconnect_navigation_mixin.dart';
 import '../utils/route_transitions.dart';
 import '../widgets/list_filter_widget.dart';
 import '../widgets/empty_state.dart';
@@ -29,6 +28,7 @@ import 'channel_chat_screen.dart';
 import 'community_qr_scanner_screen.dart';
 import 'contacts_screen.dart';
 import 'map_screen.dart';
+import 'scanner_screen.dart';
 import 'settings_screen.dart';
 
 class ChannelsScreen extends StatefulWidget {
@@ -41,7 +41,7 @@ class ChannelsScreen extends StatefulWidget {
 }
 
 class _ChannelsScreenState extends State<ChannelsScreen>
-    with DisconnectNavigationMixin {
+{
   final TextEditingController _searchController = TextEditingController();
   final CommunityStore _communityStore = CommunityStore();
   Timer? _searchDebounce;
@@ -117,11 +117,6 @@ class _ChannelsScreenState extends State<ChannelsScreen>
     final channelMessageStore = ChannelMessageStore();
     channelMessageStore.setPublicKeyHex = connector.selfPublicKeyHex;
 
-    // Auto-navigate back to scanner if disconnected
-    if (!checkConnectionAndNavigate(connector)) {
-      return const SizedBox.shrink();
-    }
-
     final allowBack = !connector.isConnected;
 
     return PopScope(
@@ -134,16 +129,33 @@ class _ChannelsScreenState extends State<ChannelsScreen>
           actions: [
             PopupMenuButton(
               itemBuilder: (context) => [
-                PopupMenuItem(
+                if (connector.isConnected)
-                  child: Row(
+                  PopupMenuItem(
-                    children: [
+                    child: Row(
-                      const Icon(Icons.logout, color: Colors.red),
+                      children: [
-                      const SizedBox(width: 8),
+                        const Icon(Icons.logout, color: Colors.red),
-                      Text(context.l10n.common_disconnect),
+                        const SizedBox(width: 8),
-                    ],
+                        Text(context.l10n.common_disconnect),
+                      ],
+                    ),
+                    onTap: () => _disconnect(context),
+                  )
+                else
+                  PopupMenuItem(
+                    child: Row(
+                      children: [
+                        const Icon(Icons.bluetooth_searching),
+                        const SizedBox(width: 8),
+                        Text(context.l10n.common_connect),
+                      ],
+                    ),
+                    onTap: () => Navigator.push(
+                      context,
+                      MaterialPageRoute(
+                        builder: (context) => const ScannerScreen(),
+                      ),
+                    ),
                   ),
-                  onTap: () => _disconnect(context),
-                ),
                 if (_communities.isNotEmpty)
                   PopupMenuItem(
                     child: Row(

lib/screens/chat_screen.dart

@@ -414,7 +414,7 @@ class _ChatScreenState extends State<ChatScreen> {
                   ],
                 ),
               ),
-              _buildInputBar(connector),
+              if (connector.isConnected) _buildInputBar(connector),
             ],
           );
         },
@@ -693,6 +693,9 @@ class _ChatScreenState extends State<ChatScreen> {
   }
 
   Future<void> _sendMessage(MeshCoreConnector connector) async {
+    if (!connector.isConnected) {
+      return;
+    }
     final text = _textController.text.trim();
     if (text.isEmpty) return;
 

lib/screens/contacts_screen.dart

@@ -19,7 +19,6 @@ import '../services/ui_view_state_service.dart';
 import '../utils/contact_search.dart';
 import '../storage/contact_group_store.dart';
 import '../utils/dialog_utils.dart';
-import '../utils/disconnect_navigation_mixin.dart';
 import '../utils/emoji_utils.dart';
 import '../utils/route_transitions.dart';
 import '../widgets/list_filter_widget.dart';
@@ -34,6 +33,7 @@ import 'chat_screen.dart';
 import 'discovery_screen.dart';
 import 'map_screen.dart';
 import 'repeater_hub_screen.dart';
+import 'scanner_screen.dart';
 import 'settings_screen.dart';
 
 enum RoomLoginDestination { chat, management }
@@ -50,7 +50,7 @@ class ContactsScreen extends StatefulWidget {
 }
 
 class _ContactsScreenState extends State<ContactsScreen>
-    with DisconnectNavigationMixin {
+{
   final TextEditingController _searchController = TextEditingController();
   final ContactGroupStore _groupStore = ContactGroupStore();
   MeshCoreConnector? _scopeSyncConnector;
@@ -306,11 +306,6 @@ class _ContactsScreenState extends State<ContactsScreen>
   Widget build(BuildContext context) {
     final connector = context.watch<MeshCoreConnector>();
 
-    // Auto-navigate back to scanner if disconnected
-    if (!checkConnectionAndNavigate(connector)) {
-      return const SizedBox.shrink();
-    }
-
     final allowBack = !connector.isConnected;
     return PopScope(
       canPop: allowBack,
@@ -378,16 +373,33 @@ class _ContactsScreenState extends State<ContactsScreen>
             ),
             PopupMenuButton(
               itemBuilder: (context) => [
-                PopupMenuItem(
+                if (connector.isConnected)
-                  child: Row(
+                  PopupMenuItem(
-                    children: [
+                    child: Row(
-                      const Icon(Icons.logout, color: Colors.red),
+                      children: [
-                      const SizedBox(width: 8),
+                        const Icon(Icons.logout, color: Colors.red),
-                      Text(context.l10n.common_disconnect),
+                        const SizedBox(width: 8),
-                    ],
+                        Text(context.l10n.common_disconnect),
+                      ],
+                    ),
+                    onTap: () => _disconnect(context, connector),
+                  )
+                else
+                  PopupMenuItem(
+                    child: Row(
+                      children: [
+                        const Icon(Icons.bluetooth_searching),
+                        const SizedBox(width: 8),
+                        Text(context.l10n.common_connect),
+                      ],
+                    ),
+                    onTap: () => Navigator.push(
+                      context,
+                      MaterialPageRoute(
+                        builder: (context) => const ScannerScreen(),
+                      ),
+                    ),
                   ),
-                  onTap: () => _disconnect(context, connector),
-                ),
                 PopupMenuItem(
                   child: Row(
                     children: [
@@ -965,6 +977,11 @@ class _ContactsScreenState extends State<ContactsScreen>
   }
 
   void _showRepeaterLogin(BuildContext context, Contact repeater) {
+    final connector = context.read<MeshCoreConnector>();
+    if (!connector.isConnected) {
+      _showCompanionRequiredDialog(context);
+      return;
+    }
     showDialog(
       context: context,
       builder: (context) => RepeaterLoginDialog(
@@ -991,6 +1008,11 @@ class _ContactsScreenState extends State<ContactsScreen>
     Contact room,
     RoomLoginDestination destination,
   ) {
+    final connector = context.read<MeshCoreConnector>();
+    if (!connector.isConnected) {
+      _showCompanionRequiredDialog(context);
+      return;
+    }
     showDialog(
       context: context,
       builder: (context) => RoomLoginDialog(
@@ -1019,6 +1041,22 @@ class _ContactsScreenState extends State<ContactsScreen>
     );
   }
 
+  void _showCompanionRequiredDialog(BuildContext context) {
+    showDialog<void>(
+      context: context,
+      builder: (dialogContext) => AlertDialog(
+        title: Text(context.l10n.scanner_notConnected),
+        content: Text(context.l10n.contact_connectCompanion),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext),
+            child: Text(context.l10n.common_ok),
+          ),
+        ],
+      ),
+    );
+  }
+
   void _confirmDeleteGroup(BuildContext context, ContactGroup group) {
     if (!_hasGroupStoreScope(context.read<MeshCoreConnector>())) {
       _showGroupsUnavailableMessage(context);

lib/screens/map_screen.dart

@@ -31,6 +31,7 @@ import '../widgets/repeater_login_dialog.dart';
 import '../widgets/room_login_dialog.dart';
 import '../helpers/snack_bar_builder.dart';
 import 'repeater_hub_screen.dart';
+import 'scanner_screen.dart';
 import 'settings_screen.dart';
 import 'line_of_sight_map_screen.dart';
 
@@ -466,16 +467,33 @@ class _MapScreenState extends State<MapScreen> {
                   ),
                 PopupMenuButton(
                   itemBuilder: (context) => [
-                    PopupMenuItem(
+                    if (connector.isConnected)
-                      child: Row(
+                      PopupMenuItem(
-                        children: [
+                        child: Row(
-                          const Icon(Icons.logout, color: Colors.red),
+                          children: [
-                          const SizedBox(width: 8),
+                            const Icon(Icons.logout, color: Colors.red),
-                          Text(context.l10n.common_disconnect),
+                            const SizedBox(width: 8),
-                        ],
+                            Text(context.l10n.common_disconnect),
+                          ],
+                        ),
+                        onTap: () => _disconnect(context, connector),
+                      )
+                    else
+                      PopupMenuItem(
+                        child: Row(
+                          children: [
+                            const Icon(Icons.bluetooth_searching),
+                            const SizedBox(width: 8),
+                            Text(context.l10n.common_connect),
+                          ],
+                        ),
+                        onTap: () => Navigator.push(
+                          context,
+                          MaterialPageRoute(
+                            builder: (context) => const ScannerScreen(),
+                          ),
+                        ),
                       ),
-                      onTap: () => _disconnect(context, connector),
-                    ),
                     PopupMenuItem(
                       child: Row(
                         children: [

lib/utils/disconnect_navigation_mixin.dart

@@ -1,20 +0,0 @@
-import 'package:flutter/material.dart';
-import '../connector/meshcore_connector.dart';
-
-/// Mixin that automatically navigates back to scanner when disconnected.
-/// Use in State classes for screens that require active connection.
-mixin DisconnectNavigationMixin<T extends StatefulWidget> on State<T> {
-  /// Call this in your Widget build method to enable auto-navigation.
-  /// Returns true if still connected, false if navigation was triggered.
-  bool checkConnectionAndNavigate(MeshCoreConnector connector) {
-    if (!connector.isConnected) {
-      WidgetsBinding.instance.addPostFrameCallback((_) {
-        if (mounted) {
-          Navigator.popUntil(context, (route) => route.isFirst);
-        }
-      });
-      return false;
-    }
-    return true;
-  }
-}