onMove method
Updates drag offset. Cancels recording if threshold is exceeded.
Implementation
void onMove(Offset offset) {
if (!_isRecording || hasText) return;
_dragOffset = offset.dx.clamp(-cancelThreshold, 0.0);
if (_dragOffset <= -cancelThreshold) {
_resetRecordingState();
}
_recordDuration = Duration.zero;
notifyListeners();
}