fix: default model edge cases

lib/features/chat/services/voice_input_service.dart

@@ -139,7 +139,7 @@ class VoiceInputService {
         path: filePath,
       );
       // ignore: avoid_print
-      print('DEBUG: VoiceInputService recording started at: ' + filePath);
+      print('DEBUG: VoiceInputService recording started at: $filePath');
 
       // Drive intensity from amplitude stream and detect silence
       // Consider amplitude less than threshold as silence; stop after ~3s of continuous silence
@@ -183,7 +183,7 @@ class VoiceInputService {
         return;
       }
       // ignore: avoid_print
-      print('DEBUG: VoiceInputService recording saved: ' + path);
+      print('DEBUG: VoiceInputService recording saved: $path');
       // Hand off recorded file path to listeners as a special token; UI layer will upload for transcription
       _textStreamController?.add('[[AUDIO_FILE_PATH]]:$path');
     } catch (e) {

lib/features/chat/views/chat_page.dart

@@ -109,7 +109,7 @@ class _ChatPageState extends ConsumerState<ChatPage> {
       
       // Try to use the default model provider
       try {
-        final model = await ref.read(defaultModelProvider.future);
+        final Model? model = await ref.read(defaultModelProvider.future);
         if (model != null) {
           debugPrint('DEBUG: Model auto-selected via provider: ${model.name}');
         }
@@ -2170,7 +2170,7 @@ class _VoiceInputSheetState extends ConsumerState<_VoiceInputSheet> {
           if (text.startsWith('[[AUDIO_FILE_PATH]]:')) {
             final filePath = text.split(':').skip(1).join(':');
             debugPrint(
-              'DEBUG: VoiceInputSheet received audio file path: ' + filePath,
+              'DEBUG: VoiceInputSheet received audio file path: $filePath',
             );
             _transcribeRecordedFile(filePath);
           } else {
@@ -2237,7 +2237,7 @@ class _VoiceInputSheetState extends ConsumerState<_VoiceInputSheet> {
         language: language,
       );
       debugPrint(
-        'DEBUG: Transcription received: ' + (text.isEmpty ? '[empty]' : text),
+        'DEBUG: Transcription received: ${text.isEmpty ? '[empty]' : text}',
       );
       if (!mounted) return;
       setState(() {

lib/features/chat/views/model_selector_page.dart

@@ -199,6 +199,7 @@ class _ModelSelectorPageState extends ConsumerState<ModelSelectorPage> {
                             onTap: () {
                               ref.read(selectedModelProvider.notifier).state =
                                   model;
+                              ref.read(isManualModelSelectionProvider.notifier).state = true;
                               Navigator.pop(context);
                             },
                           ),

lib/features/chat/widgets/message_batch_widget.dart

@@ -839,19 +839,19 @@ class MoreOptionsSheet extends ConsumerWidget {
     }
   }
 
-  void _showDeleteConfirmation(BuildContext context, WidgetRef ref) {
-    ThemedDialogs.confirm(
+  void _showDeleteConfirmation(BuildContext context, WidgetRef ref) async {
+    final confirmed = await ThemedDialogs.confirm(
       context,
       title: 'Delete Messages',
       message:
           'Are you sure you want to delete ${messages.length} message${messages.length == 1 ? '' : 's'}? This action cannot be undone.',
       confirmText: 'Delete',
       isDestructive: true,
-    ).then((confirmed) {
-      if (confirmed == true) {
-        _deleteMessages(context, ref);
-      }
-    });
+    );
+    
+    if (confirmed == true && context.mounted) {
+      _deleteMessages(context, ref);
+    }
   }
 
   void _deleteMessages(BuildContext context, WidgetRef ref) async {