feat(voice): integrate voice mode into Briefing screen

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/screens/briefing/briefing_screen.dart

@@ -11,6 +11,8 @@ import '../../widgets/chat_message_bubble.dart';
 import '../../widgets/weather_card.dart';
 import '../../widgets/news_card.dart';
 import 'briefing_history_screen.dart';
+import '../../providers/voice_provider.dart';
+import '../../widgets/voice_mic_button.dart';
 
 class BriefingScreen extends ConsumerStatefulWidget {
   const BriefingScreen({super.key});
@@ -55,6 +57,7 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen>
     WidgetsBinding.instance.removeObserver(this);
     _controller.dispose();
     _scrollController.dispose();
+    ref.read(voiceProvider.notifier).exitVoiceMode();
     super.dispose();
   }
 
@@ -106,6 +109,26 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen>
     }
   }
 
+  Future<void> _toggleVoiceMode() async {
+    final voice = ref.read(voiceProvider);
+    if (voice.voiceModeActive) {
+      ref.read(voiceProvider.notifier).exitVoiceMode();
+      return;
+    }
+    await ref.read(voiceProvider.notifier).enterVoiceMode(
+      onTranscript: (transcript) async {
+        await ref.read(briefingProvider.notifier).sendReply(transcript);
+      },
+      enableTts: true,
+      onError: (msg) {
+        if (mounted) {
+          ScaffoldMessenger.of(context)
+              .showSnackBar(SnackBar(content: Text(msg)));
+        }
+      },
+    );
+  }
+
   Future<void> _refresh() async {
     setState(() => _refreshing = true);
     try {
@@ -125,10 +148,24 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen>
   Widget build(BuildContext context) {
     final briefingAsync = ref.watch(briefingProvider);
     final isStreaming = ref.watch(isBriefingStreamingProvider);
+    final voiceState = ref.watch(voiceProvider);
     final scheme = Theme.of(context).colorScheme;
 
     // Scroll to bottom when messages change
-    ref.listen(briefingProvider, (_, _) => _scrollToBottom());
+    ref.listen(briefingProvider, (prev, next) => _scrollToBottom());
+
+    // Feed streaming assistant content to VoiceNotifier for TTS.
+    ref.listen(briefingProvider, (prev, next) {
+      if (!voiceState.voiceModeActive) return;
+      final conv = next.value;
+      if (conv == null || conv.messages.isEmpty) return;
+      final last = conv.messages.last;
+      if (last.role != MessageRole.assistant) return;
+      final isComplete = last.status != 'generating';
+      ref
+          .read(voiceProvider.notifier)
+          .feedContent(last.content, isComplete: isComplete);
+    });
 
     return Scaffold(
       appBar: AppBar(
@@ -179,7 +216,7 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen>
       ),
       body: briefingAsync.when(
         loading: () => const Center(child: CircularProgressIndicator()),
-        error: (_, _) => Center(
+        error: (err, stack) => Center(
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
@@ -248,6 +285,21 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen>
                   color: scheme.primary,
                 ),
 
+              // Voice mode banner
+              if (voiceState.voiceModeActive)
+                Container(
+                  width: double.infinity,
+                  color: const Color(0xFFEF4444).withValues(alpha: 0.12),
+                  padding: const EdgeInsets.symmetric(
+                      horizontal: 16, vertical: 6),
+                  child: const Text(
+                    '🎤 Listening… tap mic to exit voice mode',
+                    style: TextStyle(
+                      fontSize: 12,
+                      color: Color(0xFFF87171),
+                    ),
+                  ),
+                ),
               // Reply bar
               const Divider(height: 1),
               SafeArea(
@@ -258,22 +310,35 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen>
                       Expanded(
                         child: TextField(
                           controller: _controller,
-                          decoration: const InputDecoration(
-                            hintText: 'Reply to your briefing…',
-                            border: OutlineInputBorder(),
+                          decoration: InputDecoration(
+                            hintText: voiceState.voiceModeActive
+                                ? 'Listening…'
+                                : 'Reply to your briefing…',
+                            hintStyle: voiceState.voiceModeActive
+                                ? const TextStyle(fontStyle: FontStyle.italic)
+                                : null,
+                            border: const OutlineInputBorder(),
                             isDense: true,
-                            contentPadding: EdgeInsets.symmetric(
+                            contentPadding: const EdgeInsets.symmetric(
                                 horizontal: 12, vertical: 10),
                           ),
                           minLines: 1,
                           maxLines: 4,
                           textInputAction: TextInputAction.newline,
-                          enabled: !isStreaming,
+                          enabled: !isStreaming && !voiceState.voiceModeActive,
                         ),
                       ),
                       const SizedBox(width: 8),
+                      VoiceMicButton(
+                        mode: voiceState.mode,
+                        voiceModeActive: voiceState.voiceModeActive,
+                        onTap: _toggleVoiceMode,
+                      ),
+                      const SizedBox(width: 6),
                       _GradientSendButton(
-                        onPressed: isStreaming ? null : _sendReply,
+                        onPressed: (isStreaming || voiceState.voiceModeActive)
+                            ? null
+                            : _sendReply,
                         isStreaming: isStreaming,
                       ),
                     ],