Audio: footstep pulse VERIFIED end-to-end to the matcher; volume chain traced (task #50)

Footstep chain progress (each step empirically verified):
- The FootStep watcher is an AudioMatchOf<Logical> (AudioLogicalTrigger extends
  AudioMatchOf, NOT AudioTriggerOf): authored config match=1 -> Start(2.0) on a
  DirectPatchSource.  [trigcfg]/[matchcfg] ctor dumps added.
- The pulse was pinned at 1: the decay lived in IntegrateMotion, which the
  current gait path NEVER CALLS.  Moved to Mech::PerformAndWatch (provably
  per-frame) with a time-based 150ms window sized to the ~10Hz watcher poll.
  The matcher now fires per stride (14/run, was 1).
- Every footstep Start is DROPPED at the renderer: the source's volumeScale is
  0 (five VolumeAudioHandler sends of exactly 0 = inert/one-shot primes).  The
  volume arrives through the authored control chain (AudioControlMultiplier
  inputs ctl 100+; one 0 input pins the product).  Chain scales identified on
  this entity: LocalVelocity (live), LocalAcceleration (live), Myomers.
  SpeedEffect (=1.0 healthy; one authored scale maps [0,1]->[1,0] INVERTED),
  UnstablePercentage (INERT PAD -- always 0!), HeatSink.CurrentTemperature.
  PRIME SUSPECT: an UnstablePercentage-fed multiplier input primes 0 once and
  never updates (the pad never changes), pinning footstep volume at 0.
- SF2 numbering fact recorded: 38 presets in AUDIO1 / 5 in AUDIO2 have
  wPreset != file index (gap at preset 77); my table keys by wPreset.  The
  184x ProgramButton01 (bank1 patch83) storm at ~7/s needs an identity check
  against index-numbering (it may be the wrong sample for that patch id).

Diagnostics added (BT_AUDIO_SPATIAL/BT_ATTRBIND_LOG): [trigcfg]/[matchcfg]
ctor dumps, [matchfire] with component ptr+class, [volset] VolumeAudioHandler,
[mult0] multiplier zero-products, scale sends with authored boundaries,
[fswatch] dedicated footstep watcher tracer (g_btFootStepAddr), SetupPatch
ENTRY with bank/patch/state, Simulation::DebugAudioWatcherCount.

NEXT: back UnstablePercentage with a real (live) member -- it is the mech's
stability 0..1 (the stabilityAlarm/gyro family) -- or confirm via a one-run
chain dump which multiplier input pins the FS source; then the footstep
transient should clear the 0.3 drop gate at walking speed.

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

game/reconstructed/mech4.cpp

@@ -292,10 +292,8 @@ Logical
 	// Choose this frame's forward-cycle slew rate.
 	forwardCycleRate = airborneSelect ? airborneCycleRate : groundCycleRate;	// 0x344<-0x5bc/0x5b8
 
-	// FootStep pulse decay (see SetBodyAnimation): clear the contact flag a few
-	// frames after the plant so the AudioLogicalTrigger re-arms for the next step.
-	if (footStepDecay > 0 && --footStepDecay == 0)
-		footStep = 0;
+	// (FootStep pulse decay moved to PerformAndWatch -- this integrator does not
+	// run on the current gait path, so a decay here never fired.)
 
 	if (IsDisabled())								// FUN_0049fb54
 	{
@@ -5205,6 +5203,21 @@ void
 	// (AudioLogicalTrigger FootStep, AudioMotionScale/Trigger LocalVelocity, ...)
 	// never executed -- only the PUSHED StateIndicator watchers fired.  That's
 	// why footsteps/motion-scaled sounds were silent while state sounds worked.  [T0]
+	// FootStep pulse decay (see SetBodyAnimation): clear the contact flag ~150ms
+	// after the plant so the FootStep matcher (fires on the CHANGE to 1) sees a 0
+	// before the next stride re-pulses.  Lives HERE (not IntegrateMotion, which the
+	// current gait path never calls) so it provably ticks every mech frame, right
+	// before the watcher poll below reads it.  Time-based -- tick-rate immune.
+	if (footStepDecay > 0)
+	{
+		footStepDecay -= (int)(dt * 1000.0f);
+		if (footStepDecay <= 0)
+		{
+			footStepDecay = 0;
+			footStep      = 0;
+		}
+	}
+
 	if (getenv("BT_AUDIO_LOG")) { static int s_wd=0; if ((s_wd++ % 300)==0)
 		DEBUG_STREAM << "[audio] mech watcher poll: delayed=" << (int)AreWatchersDelayed() << " audioWatchers=" << DebugAudioWatcherCount()
 			<< " simFlags=0x" << std::hex << (unsigned)simulationFlags << std::dec