Decouple voice progress from amplitude stream

lib/screens/mapflow_shell.dart

@@ -727,12 +727,14 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
 
   Future<List<PlaceRecommendation>>? _nearbyPlacesFuture;
   StreamSubscription<record.Amplitude>? _amplitudeSub;
+  Timer? _progressTimer;
   XFile? _recordedFile;
   var _step = 0;
   var _informationUnits = 0.0;
   var _recording = false;
   var _submitting = false;
   var _micAllowed = true;
+  var _heardVoice = false;
   var _noiseDb = -72.0;
   var _voicePeakDb = -34.0;
   var _liveLevel = 0.0;
@@ -746,6 +748,7 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
   @override
   void dispose() {
     _amplitudeSub?.cancel();
+    _progressTimer?.cancel();
     _audioRecorder.dispose();
     super.dispose();
   }
@@ -783,10 +786,16 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
     _amplitudeSub = _audioRecorder
         .onAmplitudeChanged(_amplitudeInterval)
         .listen(_handleAmplitude);
+    _progressTimer?.cancel();
+    _progressTimer = Timer.periodic(
+      _amplitudeInterval,
+      (_) => _tickRecordingProgress(),
+    );
 
     setState(() {
       _micAllowed = true;
       _recording = true;
+      _heardVoice = false;
       _liveLevel = 0;
       _informationUnits = 0;
     });
@@ -795,6 +804,8 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
   Future<void> _stopRecording() async {
     await _amplitudeSub?.cancel();
     _amplitudeSub = null;
+    _progressTimer?.cancel();
+    _progressTimer = null;
     final path = await _audioRecorder.stop();
     _recordStopwatch.stop();
     if (path != null && path.isNotEmpty) {
@@ -812,12 +823,26 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
 
   void _handleAmplitude(record.Amplitude amplitude) {
     final currentDb = amplitude.current;
-    final now = DateTime.now();
     final level = _normalizeDbLevel(currentDb);
-    final informationDelta = _consumeInformationDelta(level, now);
 
     setState(() {
       _liveLevel = _smoothLevel(_liveLevel, level);
+      _heardVoice = _heardVoice || level > 0.08;
+    });
+  }
+
+  void _tickRecordingProgress() {
+    if (!_recording) {
+      return;
+    }
+
+    final effectiveLevel = _heardVoice ? math.max(_liveLevel, 0.34) : _liveLevel;
+    final informationDelta = _consumeInformationDelta(
+      effectiveLevel,
+      DateTime.now(),
+    );
+
+    setState(() {
       _informationUnits = math.min(
         _minimumInformationUnits,
         _informationUnits + informationDelta,