voiceOnDucking method
Voice Ducking Hook
Called by VoiceActingChannel when a voice line starts.
Caches the current BGM volume and then reduces it to a softer level
(default 0.3) to keep narration intelligible without hard-stopping music.
Note: Adjust the target value to taste or expose it via config.
Implementation
Future<void> voiceOnDucking() async {
_bgmCachedVolume = bgm.volume;
await bgm.setVolume(0.3);
}