feat(assistant): Add model selection for Android Assistant

lib/core/services/settings_service.dart

@@ -60,6 +60,7 @@ class SettingsService {
       PreferenceKeys.voiceSilenceDuration;
   static const String _androidAssistantTriggerKey =
       PreferenceKeys.androidAssistantTrigger;
+  static const String _androidAssistantModelKey = 'android_assistant_model';
   static Box<dynamic> _preferencesBox() =>
       Hive.box<dynamic>(HiveBoxNames.preferences);
 
@@ -145,6 +146,23 @@ class SettingsService {
     return box.delete(_defaultModelKey);
   }
 
+  /// Get Android Assistant Model preference
+  static Future<String?> getAndroidAssistantModelId() {
+    final value = _preferencesBox().get(_androidAssistantModelKey) as String?;
+    return Future.value(value);
+  }
+
+
+
+  /// Set Android Assistant Model preference
+  static Future<void> setAndroidAssistantModelId(String? modelId) {
+    final box = _preferencesBox();
+    if (modelId != null) {
+      return box.put(_androidAssistantModelKey, modelId);
+    }
+    return box.delete(_androidAssistantModelKey);
+  }
+
   /// Load all settings
   static Future<AppSettings> loadSettings() {
     final box = _preferencesBox();
@@ -184,6 +202,12 @@ class SettingsService {
       await box.delete(_defaultModelKey);
     }
 
+    if (settings.androidAssistantModelId != null) {
+      await box.put(_androidAssistantModelKey, settings.androidAssistantModelId);
+    } else {
+      await box.delete(_androidAssistantModelKey);
+    }
+
     if (settings.voiceLocaleId != null && settings.voiceLocaleId!.isNotEmpty) {
       await box.put(_voiceLocaleKey, settings.voiceLocaleId);
     } else {
@@ -436,6 +460,7 @@ class SettingsService {
       androidAssistantTrigger: _parseAndroidAssistantTrigger(
         box.get(_androidAssistantTriggerKey) as String?,
       ),
+      androidAssistantModelId: box.get(_androidAssistantModelKey) as String?,
       voiceSilenceDuration: (box.get(_voiceSilenceDurationKey) as int? ?? 2000)
           .clamp(300, 3000),
     );
@@ -471,6 +496,7 @@ class AppSettings {
   final String? ttsServerVoiceId;
   final String? ttsServerVoiceName;
   final AndroidAssistantTrigger androidAssistantTrigger;
+  final String? androidAssistantModelId;
   final int voiceSilenceDuration;
   const AppSettings({
     this.reduceMotion = false,
@@ -495,6 +521,7 @@ class AppSettings {
     this.ttsServerVoiceId,
     this.ttsServerVoiceName,
     this.androidAssistantTrigger = AndroidAssistantTrigger.overlay,
+    this.androidAssistantModelId,
     this.voiceSilenceDuration = 2000,
   });
 
@@ -522,6 +549,7 @@ class AppSettings {
     Object? ttsServerVoiceName = const _DefaultValue(),
     int? voiceSilenceDuration,
     AndroidAssistantTrigger? androidAssistantTrigger,
+    Object? androidAssistantModelId = const _DefaultValue(),
   }) {
     return AppSettings(
       reduceMotion: reduceMotion ?? this.reduceMotion,
@@ -555,6 +583,9 @@ class AppSettings {
           : ttsServerVoiceName as String?,
       androidAssistantTrigger:
           androidAssistantTrigger ?? this.androidAssistantTrigger,
+      androidAssistantModelId: androidAssistantModelId is _DefaultValue
+          ? this.androidAssistantModelId
+          : androidAssistantModelId as String?,
       voiceSilenceDuration: voiceSilenceDuration ?? this.voiceSilenceDuration,
     );
   }
@@ -581,8 +612,10 @@ class AppSettings {
         other.ttsVolume == ttsVolume &&
         other.ttsEngine == ttsEngine &&
         other.ttsServerVoiceId == ttsServerVoiceId &&
-        other.ttsServerVoiceName == ttsServerVoiceName &&
+
+
         other.androidAssistantTrigger == androidAssistantTrigger &&
+        other.androidAssistantModelId == androidAssistantModelId &&
         other.voiceSilenceDuration == voiceSilenceDuration &&
         _listEquals(other.quickPills, quickPills);
     // socketTransportMode intentionally not included in == to avoid frequent rebuilds
@@ -611,7 +644,9 @@ class AppSettings {
       ttsEngine,
       ttsServerVoiceId,
       ttsServerVoiceName,
+
       androidAssistantTrigger,
+      androidAssistantModelId,
       voiceSilenceDuration,
       Object.hashAllUnordered(quickPills),
     ]);
@@ -796,6 +831,11 @@ class AppSettingsNotifier extends _$AppSettingsNotifier {
     await SettingsService.setAndroidAssistantTrigger(trigger);
   }
 
+  Future<void> setAndroidAssistantModelId(String? modelId) async {
+    state = state.copyWith(androidAssistantModelId: modelId);
+    await SettingsService.setAndroidAssistantModelId(modelId);
+  }
+
   Future<void> resetToDefaults() async {
     const defaultSettings = AppSettings();
     await SettingsService.saveSettings(defaultSettings);

lib/core/utils/android_assistant_handler.dart

@@ -11,6 +11,7 @@ import '../services/navigation_service.dart';
 import '../../shared/services/tasks/task_queue.dart';
 import '../providers/app_providers.dart';
 import '../../features/auth/providers/unified_auth_providers.dart';
+import '../services/settings_service.dart';
 import 'debug_logger.dart';
 
 final androidAssistantProvider = Provider(
@@ -78,8 +79,11 @@ class AndroidAssistantHandler {
         return;
       }
 
-      // Start a fresh chat context
-      startNewChat(_ref);
+      // Start a fresh chat context with specific model preference
+      final settings = _ref.read(appSettingsProvider);
+      final specificModelId = settings.androidAssistantModelId;
+
+      startNewChat(_ref, specificModelId: specificModelId);
 
       // Add screenshot as attachment
       final file = File(screenshotPath);
@@ -189,20 +193,27 @@ class AndroidAssistantHandler {
       DebugLogger.log('Starting new chat from assistant', scope: 'assistant');
 
       final navState = _ref.read(authNavigationStateProvider);
-      final model = _ref.read(selectedModelProvider);
-
-      if (navState != AuthNavigationState.authenticated || model == null) {
-        DebugLogger.log('App not ready for new chat', scope: 'assistant');
-        return;
+      // final model = _ref.read(selectedModelProvider); // We verify model availability inside startNewChat or by checking if we have *any* model later, 
+      // but for "readiness" we mainly care about auth. 
+      // Actually, existing check wanted `model != null`. 
+      // If we are overriding, we might not have a selected model yet.
+
+      if (navState != AuthNavigationState.authenticated) {
+         DebugLogger.log('App not ready for new chat (auth)', scope: 'assistant');
+         return;
       }
 
       final isOnChatRoute = NavigationService.currentRoute == Routes.chat;
       if (!isOnChatRoute) {
         await NavigationService.navigateToChat();
       }
 
-      startNewChat(_ref);
-      DebugLogger.log('New chat started from assistant', scope: 'assistant');
+      // Check for specific assistant model preference
+      final settings = _ref.read(appSettingsProvider);
+      final specificModelId = settings.androidAssistantModelId;
+
+      startNewChat(_ref, specificModelId: specificModelId);
+      DebugLogger.log('New chat started from assistant (model: $specificModelId)', scope: 'assistant');
     } catch (e) {
       DebugLogger.log('Failed to start new chat: $e', scope: 'assistant');
     }

lib/features/chat/providers/chat_providers.dart

@@ -10,6 +10,7 @@ import 'package:yaml/yaml.dart' as yaml;
 import '../../../core/auth/auth_state_manager.dart';
 import '../../../core/models/chat_message.dart';
 import '../../../core/models/conversation.dart';
+import '../../../core/models/model.dart';
 import '../../../core/providers/app_providers.dart';
 import '../../../core/services/conversation_delta_listener.dart';
 import '../../../core/services/settings_service.dart';
@@ -887,7 +888,7 @@ String? _extractSystemPromptFromSettings(Map<String, dynamic>? settings) {
 }
 
 // Start a new chat (unified function for both "New Chat" button and home screen)
-void startNewChat(dynamic ref) {
+void startNewChat(dynamic ref, {String? specificModelId}) {
   // Clear active conversation
   ref.read(activeConversationProvider.notifier).clear();
 
@@ -901,15 +902,33 @@ void startNewChat(dynamic ref) {
   ref.read(pendingFolderIdProvider.notifier).clear();
 
   // Reset to default model for new conversations (fixes #296)
-  restoreDefaultModel(ref);
+  restoreDefaultModel(ref, specificModelId: specificModelId);
 }
 
-/// Restores the selected model to the user's configured default model.
+/// Restores the selected model to the user's configured default model or a specific one.
 /// Call this when starting a new conversation or when settings change.
-Future<void> restoreDefaultModel(dynamic ref) async {
+Future<void> restoreDefaultModel(dynamic ref, {String? specificModelId}) async {
   // Mark that this is not a manual selection
   ref.read(isManualModelSelectionProvider.notifier).set(false);
 
+  if (specificModelId != null) {
+    // Attempt to set specific model
+    final modelsAsync = ref.read(modelsProvider);
+    List<Model> models = [];
+    if (modelsAsync.hasValue) {
+      models = modelsAsync.value!;
+    } else {
+      models = await ref.read(modelsProvider.future);
+    }
+
+    final specificModel = models.where((m) => m.id == specificModelId).firstOrNull;
+    if (specificModel != null) {
+      ref.read(selectedModelProvider.notifier).set(specificModel);
+      return;
+    }
+    // Fallback if specific model not found: continue to standard default logic
+  }
+
   // If auto-select (no explicit default), clear the cached default model
   // so defaultModelProvider will fetch from server
   final settingsDefault = ref.read(appSettingsProvider).defaultModel;