Implement CONFIG mixer and native profile persistence

engine/Age.Engine/Hosting/IHost.cs

@@ -141,6 +141,9 @@ public interface IHost
     void ScheduleSoundEffectStart(int channel, int startMode, long delayMs) { }
     void ReleaseSoundEffect(int channel) { }
     void FadeBgm(int targetPercent, long durationMs) { }
+    // AGE's sound:* settings registry is VM-owned; the host applies changes to active playback.
+    void ApplyAudioVolume(int category, int basisPoints) { }
+    void ApplyAudioRouteEnabled(int category, bool enabled) { }
     // Native op 0x236 binds a movie decoder to an existing retained texture surface.
     // Playback is non-modal: the VM advances to the following instruction while the host publishes frames.
     /// <returns>The initialized movie graph's stop position in truncated integer milliseconds, or null