Make voice grid visibly animate

lib/screens/mapflow_shell.dart

@@ -737,6 +737,7 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
 
   Future<List<PlaceRecommendation>>? _nearbyPlacesFuture;
   StreamSubscription<Amplitude>? _amplitudeSub;
+  Timer? _visualTimer;
   var _step = 0;
   var _informationUnits = 0.0;
   var _recording = false;
@@ -745,7 +746,9 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
   var _noiseDb = -72.0;
   var _voicePeakDb = -34.0;
   var _liveLevel = 0.0;
+  var _visualPhase = 0.0;
   DateTime? _lastInformationAt;
+  DateTime? _lastAmplitudeAt;
 
   @override
   void initState() {
@@ -755,6 +758,7 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
   @override
   void dispose() {
     _amplitudeSub?.cancel();
+    _visualTimer?.cancel();
     _waveController.dispose();
     super.dispose();
   }
@@ -784,7 +788,9 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
     await _waveController.startRecording();
     await _amplitudeSub?.cancel();
     _lastInformationAt = DateTime.now();
+    _lastAmplitudeAt = null;
     _amplitudeSub = _waveController.amplitudeStream.listen(_handleAmplitude);
+    _startVisualTick();
 
     setState(() {
       _micAllowed = true;
@@ -798,8 +804,11 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
   Future<void> _stopRecording() async {
     await _amplitudeSub?.cancel();
     _amplitudeSub = null;
+    _visualTimer?.cancel();
+    _visualTimer = null;
     await _waveController.stopRecording();
     _lastInformationAt = null;
+    _lastAmplitudeAt = null;
     if (!mounted) {
       return;
     }
@@ -813,12 +822,16 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
     final currentDb = amplitude.current;
     final now = DateTime.now();
     final level = _normalizeDbLevel(currentDb);
-    final informationDelta = _consumeInformationDelta(level, now);
+    final informationLevel = currentDb > -64
+        ? math.max(0.22, level)
+        : level * 0.35;
+    final informationDelta = _consumeInformationDelta(informationLevel, now);
+    _lastAmplitudeAt = now;
 
     setState(() {
       _voiceSamples
         ..removeAt(0)
-        ..add(level);
+        ..add(math.max(0.04, level));
       _liveLevel = _smoothLevel(_liveLevel, level);
       _informationUnits = math.min(
         _minimumInformationUnits,
@@ -830,6 +843,30 @@ class _AddExperienceFlowState extends ConsumerState<AddExperienceFlow> {
         .setReviewDuration(_waveController.timeElapsed);
   }
 
+  void _startVisualTick() {
+    _visualTimer?.cancel();
+    _visualTimer = Timer.periodic(const Duration(milliseconds: 70), (_) {
+      if (!mounted || !_recording) {
+        return;
+      }
+
+      _visualPhase += 0.34;
+      final hasFreshAmplitude =
+          _lastAmplitudeAt != null &&
+          DateTime.now().difference(_lastAmplitudeAt!).inMilliseconds < 160;
+      final baseLevel = hasFreshAmplitude ? _liveLevel : 0.10;
+      final wave =
+          (math.sin(_visualPhase) * 0.5 + 0.5) * (0.16 + baseLevel * 0.34);
+      final visualLevel = (0.06 + baseLevel * 0.70 + wave).clamp(0.0, 1.0);
+
+      setState(() {
+        _voiceSamples
+          ..removeAt(0)
+          ..add(visualLevel);
+      });
+    });
+  }
+
   double _normalizeDbLevel(double currentDb) {
     final db = currentDb.clamp(-160.0, 0.0);
     if (db < _noiseDb) {
@@ -1095,7 +1132,7 @@ class _VoiceStep extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final canFinish = canContinue && !isRecording;
+    final canFinish = canContinue;
 
     return Column(
       children: [
@@ -1392,7 +1429,8 @@ class _VoiceInformationPainter extends CustomPainter {
         final signal = samples.isEmpty
             ? 0.0
             : samples[sampleIndex].clamp(0.0, 1.0);
-        final filled = _cellOrder(cellIndex, totalCells) < activeCells;
+        final fillOrder = (rows - 1 - row) * columns + column;
+        final filled = fillOrder < activeCells;
         final x = startX + column * (cellSize + gap);
         final y = startY + row * (cellSize + gap);
         final rect = RRect.fromRectAndRadius(
@@ -1442,8 +1480,6 @@ class _VoiceInformationPainter extends CustomPainter {
     }
   }
 
-  int _cellOrder(int index, int total) => ((index + 11) * 73) % total;
-
   double _hashUnit(int index) {
     final value = math.sin(index * 12.9898 + 78.233) * 43758.5453;
     return value - value.floorToDouble();