Implement held ADV fast-forward input

engine/Age.Engine/Hosting/IHost.cs

@@ -71,6 +71,9 @@ public interface IHost
     // Native 0x1c7/0x1cc query two distinct ADV skip channels. Headless and non-interactive
     // hosts default to normal playback; the Godot host supplies the live interactive values.
     void SetMessageSkipActive(bool active) { }
+    // Logical action 6 is the native hold-to-fast-forward channel. Keep it separate from the
+    // persistent op-0x88 channel so releasing the key cannot turn off the user's Skip toggle.
+    void SetPhysicalMessageSkipActive(bool active) { }
     bool IsMessageSkipActive => false;
     bool IsAdvReadSkipActive => false;
     // Normal playback reaches op 0x21c and parks until a queued 0x223 transition completes. The