#110: the zone destruction cascade is LIVE -- an arm now takes its gun pod with it

Lynx: "You can destroy an upper arm, and the gun pod is intact and can still
fire."  Conn Man's audit: three chassis, both arms, reproducible.  And the user
is right that this family was claimed fixed before: #86 gated fire on the
WEAPON's own destruction and was verified by destroying the weapon directly
(BT_KILL_SUBSYS) -- the field scenario was the ARM ZONE dying with the weapon
subsystem healthy, which that bench never reproduced.  Oracle's 693-night "I can
still fire destroyed energy weapons" was almost certainly this mechanism.

ROOT CAUSE -- a silent stub.  Mech__DamageZone::RecurseSegmentTable @0049cad4
was transcribed faithfully... against three local shim types whose iterators
unconditionally return NULL:
    struct SegmentIterator { DZRef *Next() { return 0; } };
    struct SegTableX       { SegmentRecord *operator[](int) { return 0; } };
The cascade fired on zone death (bench: 72 [cascade] lines), "descended", and
touched nothing.  Every line read correct; none of it did anything.

THE REAL WALK (decomp re-read, FUN_0049cad4): iterate the mech's segment table
(mech+0x300, vtbl+0x34 GetNth) to this zone's segment, then
    destroySiblingsOnDestruction (Wword 0x68): recurse every other zone on the
        SAME segment (seg+0xD0), setting graphic state 2 (Gone)
    descendOnDestruction (Wword 0x67): recurse every zone on every CHILD
        segment (seg+0xE8 -> child+0xD0) -- the arm takes the gun
The engine ALREADY HAS both structures: EntitySegment::damageZoneTable @0xD0 /
childIndexTable @0xE8 (TableOf is 0x18 -- byte-identical to the decomp offsets),
populated at stream time by JMOVER.cpp:373 [T0].  The stub was never necessary.
Implemented with the engine iterators via two new read accessors on
EntitySegment (SEGMENT.h); the binary's asymmetry is reproduced as-is (the
sibling loop checks graphic state != 1, the child loop does not; re-hits on a
1.0 zone re-run the cascade -- idempotent in effect).

VERIFIED (ava1, self-damage to one zone, autofire everything):
  dz_rarm -> [cascade] zone 9 -> zone 17; AFC100 + AmmoBinAFC100 + Condenser6
      ForceCriticalFailure'd; "[ammo] AFC100 -> NoAmmo (gate1): destroyed=1";
      torso LRM5/SRM2 keep firing (correct)
  dz_larm -> [cascade] zone 2 -> zone 6; PPC + Condenser4 force-failed;
      "[emitter] 'PPC' fire REFUSED (destroyed=1)" x4998 -- the emitter gate now
      logs refusals BY NAME (the FIRED line never named its weapon, which is how
      #86's verification gap survived)
  regression smoke: frame time 7.13/7.20ms, 0 asserts, 0 cascades in ordinary
      combat (they fire only on genuine zone deaths)

Authored data (now dumped under BT_DMG_LOG): descend=1 on exactly the four arm
zones (ava1: 2/6/9/17), destroySibs=0 everywhere -- so legs/torso behavior is
untouched by this change.

KB: combat-damage.md cascade section; reconstruction-gotchas #26 (the
silent-stub trap: a shim that returns EMPTY converts a reconstruction into
fiction that reads correct -- shims must Fail() loudly or log their emptiness).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

game/reconstructed/emitter.cpp

@@ -436,6 +436,14 @@ void
 	if (simulationState == 1 || statusAlarm.GetLevel() == 1
 		|| GetFaultState() == 2 || BTMechDestroyed((Entity *)owner))
 	{
+		// #110 verification: name the refusal, so "the destroyed PPC stays
+		// silent" is a log fact rather than an inference (the FIRED line does
+		// not name its weapon).  Once per weapon per destruction is enough --
+		// keyed on the firing state actually being reset.
+		if (getenv("BT_DMG_LOG") && GetWeaponState() != 0)
+			DEBUG_STREAM << "[emitter] '" << (GetName() ? GetName() : "?")
+				<< "' fire REFUSED (destroyed=" << (int)(simulationState == 1
+					|| statusAlarm.GetLevel() == 1) << ")" << std::endl;
 		ResetFiringState();								// @004ba9a8
 		currentLevel = 0.0f;							// 0x414
 		ComputeOutputVoltage();							// (*vtable+0x44)()