audio: gated [statefire] diagnostic on AudioStateTrigger (BT_AUDIO_SPATIAL)

Logs animation-range state-trigger fires (trigState>=5, capped 60).  Used to
prove the #78 limp audio end-to-end: entering the gimp states fires the
authored strained-servo component (statefire trigState=23 old=7 new=23,
ctl Start) -- the 1995 wounded-leg sound, reachable for the first time now
that the limp gait lands.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

engine/MUNGA/AUDWTHR.cpp

@@ -1079,6 +1079,12 @@ void
 	{
 		Check(&audioComponentSocket);
 		Check(audioComponentSocket.GetCurrent());
+		if (triggerState >= 5 && getenv("BT_AUDIO_SPATIAL")) { static int s_sf=0; if (s_sf++<60)
+			DEBUG_STREAM << "[statefire] trigState=" << triggerState
+				<< " old=" << old_state << " new=" << new_state
+				<< " comp=" << (void*)audioComponentSocket.GetCurrent()
+				<< " ctl=" << (int)controlID << "/" << controlValue
+				<< "\n" << std::flush; }
 		#if 1
 		audioComponentSocket.GetCurrent()->ReceiveControl(
 			controlID,