Audio: restore the dropped ExecuteWatchers poll -- polled audio watchers were ALL dead (task #50)

User: "when I start moving all the sounds fade away, no footsteps."  Diagnosis
chain (all empirical, BT_AUDIO_SPATIAL/BT_ATTRBIND_LOG traces):
- The audio head DOES track the mech (listener-relative positioning verified
  while driving) -- not a spatial bug.
- The idle sounds correctly STOP on leaving the standing state; the MOVING
  sounds never started because every POLLED audio watcher was dead:
  the reconstructed Mech::PerformAndWatch replaced the engine performance but
  dropped the ExecuteWatchers() step from the engine tail (Simulation::
  PerformAndWatch = Perform -> ExecuteWatchers -> WriteSimulationUpdate).
  Only PUSHED StateIndicator watchers (SetState->Execute) ever fired -- which
  is exactly why state sounds worked but footsteps/motion-scaled audio didn't.
  FIX: poll ExecuteWatchers() (AreWatchersDelayed-gated) before the update
  write.  Immediately unlocks the polled family: MissileLoaded01/LaserLoaded01
  ready dings, ProgramButton01, motion scales (PlayNote 15 -> 30 per run).

- FootStep (0x1e) backed REAL: was the inert attrPad (an AudioLogicalTrigger
  polls it -- threshold-crossing pulse per foot plant).  New footStep member,
  pulsed by SetBodyAnimation on entering any locomotion clip 1..0x17 (runtime
  stride alternation MEASURED as body states 12<->13 -- the enum-name numbering
  does not match runtime clip ids), decayed by IntegrateMotion (~1/3 s).
- Footstep volume is speed-scaled (AudioMotionScale on LocalVelocity): at
  standstill the transient start computes volume 0 and the renderer drops it
  (LowAudioVolumeThreshold) -- so footfalls are audible at real walking speed.

Diagnostics kept (BT_AUDIO_SPATIAL): spatial dist/vol per source, CLIPPED/DROP/
START at the request gate, vol=0 factor breakdown, scale->0 sends, trigger
notifications, watcher poll-rate probe.

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

game/reconstructed/mech.cpp

@@ -711,7 +711,7 @@ const Mech::IndexEntry
 	ATTRIBUTE_ENTRY(Mech, MaxRunSpeed,             reverseStrideLength),	// 0x1b (existing @0x34c = run/top speed)
 	ATTRIBUTE_ENTRY(Mech, EyepointRotation,        eyepointRotation),		// 0x1c (real member -- the eye reads it per frame)
 	ATTRIBUTE_ENTRY(Mech, TargetReticle,           targetReticle),		// 0x1d (real Reticle struct -- task #36)
-	ATTRIBUTE_ENTRY(Mech, FootStep,                attrPad),				// 0x1e
+	ATTRIBUTE_ENTRY(Mech, FootStep,                footStep),				// 0x1e real pulse (AudioLogicalTrigger; one rising edge per foot plant)
 	ATTRIBUTE_ENTRY(Mech, AnimationState,          animationState),			// 0x1f real StateIndicator (audio state-watcher binds + AddAudioWatcher)
 	ATTRIBUTE_ENTRY(Mech, ReplicantAnimationState, replicantAnimationState),	// 0x20 real StateIndicator
 	ATTRIBUTE_ENTRY(Mech, LinearSpeed,             linearSpeed),			// 0x21 (live forward speed)
@@ -923,6 +923,8 @@ Mech::Mech(
 	collisionState          = StateIndicator(4);	// CollisionStateCount
 	collisionState.SetState(0);						// NoCollisionState
 	collisionTemporaryState = 0;
+	footStep                = 0;					// FootStep pulse (audio trigger)
+	footStepDecay           = 0;
 	radarRange          = 1000.0f;						// radar display scale (SetTargetRange is stubbed;
 														// 1km default zoom so contacts within ~500m show on
 														// the radar, vs the config maximum_range=4000 edge)

game/reconstructed/mech.hpp

@@ -841,6 +841,14 @@ protected:
 		// scrape sounds).  Driven from ProcessCollision via collisionTemporaryState:
 		// NoCollision(0)/InitialHit(1)/Slide(2)/Rest(3) (RP VTV CollisionStateCount).
 		StateIndicator	collisionState;
+		// 0x1e FootStep -- audio binds an AudioLogicalTrigger (threshold-crossing
+		// with hysteresis: rise past threshold -> play the step, fall back -> re-arm).
+		// Backed by a real pulse: SetBodyAnimation raises it 1 on entering a cyclic
+		// stride clip (each walk/run/reverse alternation == one foot plant) and the
+		// per-frame motion tick decays it back to 0 a few frames later, giving one
+		// clean rising edge per step.  [T2]
+		int				footStep;			// the Logical the trigger polls (1 = contact)
+		int				footStepDecay;		// frames until the pulse clears
 		// Radar/map gauge attributes (binary @0x404/0x408/0x40c/0x3f8).  The map
 		// widget reads position/angle as POINTERS into the mech's live origin, so
 		// radarLinearPosition/radarAngularPosition point at localOrigin.{linear,

game/reconstructed/mech2.cpp

@@ -249,6 +249,22 @@ void
 		animationState.SetState(state);
 		replicantAnimationState.SetState(state);
 	}
+
+	// FootStep pulse: every locomotion-clip transition is one foot plant (the
+	// stride R<->L alternation -- MEASURED at runtime: forward walking alternates
+	// body states 12<->13, so the enum-name numbering above does NOT match the
+	// runtime clip ids; key on the locomotion RANGE instead).  Clips 1..0x17 are
+	// the gait cycle (stand-to-walk through gimp); 0 = standing, >= 0x18 = falls/
+	// knockdown/death (those get collision/fall audio, not a step).  Raise the
+	// Logical the FootStep AudioLogicalTrigger polls; IntegrateMotion decays it
+	// back to 0 a few frames later so each step is a clean rising edge.  [T2]
+	if (state >= 1 && state <= 0x17)
+	{
+		footStep      = 1;
+		footStepDecay = 20;				// ~1/3s: outlives the watcher poll cadence (still < stride period)
+		if (getenv("BT_AUDIO_LOG")) { static int s_fs=0; if (s_fs++<40)
+			DEBUG_STREAM << "[audio] footstep pulse (clip " << state << ") addr=" << (void*)&footStep << "\n" << std::flush; }
+	}
 }
 
 //

game/reconstructed/mech4.cpp

@@ -292,6 +292,11 @@ 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;
+
 	if (IsDisabled())								// FUN_0049fb54
 	{
 		ReconQuatIdentity(&angularAccum, &kIdentityQuat);		// was raw this+0x298 (stomped projectedVelocity)
@@ -5193,6 +5198,16 @@ void
 	// writer re-dispatches SetBodyAnimation on the WRITER -- the real-clock crash
 	// rode this path with legAnimationState still 0xCDCDCDCD).  Discard replicant
 	// marks instead.
+	// WATCHER POLL (engine Simulation::PerformAndWatch tail, SIMULATE.cpp:460):
+	// the engine path ends Perform() -> ExecuteWatchers() -> WriteSimulationUpdate().
+	// This reconstruction replaced the whole performance but DROPPED the
+	// ExecuteWatchers() step, so the entity-level POLLED audio watchers
+	// (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]
+	if (!AreWatchersDelayed())
+		ExecuteWatchers();
+
 	if (GetInstance() != ReplicantInstance)
 		WriteSimulationUpdate(update_stream);
 	else