Audio: footstep-chain diagnostics -- every link verified except the final trigger fire (task #50)

Instrumentation (all BT_AUDIO_LOG/BT_AUDIO_SPATIAL-gated): mech watcher-poll
probe (delayed flag + socket count via new Simulation::DebugAudioWatcherCount),
per-sim audio-socket size in ExecuteWatchers, trigger notifications (val>0),
watcher poll-rate/change probes, footstep pulse address trace.

VERIFIED working: FootStep binds to the real member (pulse addr == bound ptr,
same run); pulses fire per stride (40/run); the watcher registers on the mech
(audioWatchers=20 after audio-object creation); the mech's poll runs
(delayed=0, simFlags=0x1110); Logical == int (STYLE.H:132) matches the member
type.  The idle<->moving engine crossfade (AudioMotionScale on LocalVelocity
through the restored watcher poll) is CONFIRMED audible in play.

REMAINING: the FootFall transient still doesn't reach SetupPatch -- next probe
is the trigger's streamed threshold/inverse config and the speed-scaled
transient volume at the renderer drop gate (LowAudioVolumeThreshold=0.3).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

engine/MUNGA/SIMULATE.cpp

@@ -1,3 +1,4 @@
+#include <cstdlib>
 #include "munga.h"
 #pragma hdrstop
 
@@ -486,6 +487,14 @@ void
 //#############################################################################
 // Watcher Support
 //
+int
+	Simulation::DebugAudioWatcherCount()
+{
+	SChainIteratorOf<Component*> iterator(audioWatcherSocket);
+	return (int)iterator.GetSize();
+}
+
+
 void
 	Simulation::ExecuteWatchers()
 {
@@ -496,6 +505,8 @@ void
 	// Audio
 	{
 		SChainIteratorOf<Component*> iterator(audioWatcherSocket);
+		if (getenv("BT_AUDIO_SPATIAL")) { static int s_ec=0; if ((s_ec++ % 600)==0)
+			DEBUG_STREAM << "[watchpoll] sim=" << (void*)this << " audioSocket size=" << iterator.GetSize() << "\n" << std::flush; }
 		while ((watcher = iterator.ReadAndNext()) != NULL)
 		{
 			watcher->Execute();