#124 CORRECTION: the frame adapter is a Z-REFLECTION, not a pi rotation --

proven by the mech's own pods

The first fix (c5dfb00) negated x AND z. The operator challenged it:
'they couldn't hit rear panels AT ALL -- a 180 rotation couldn't explain
that' -- and a rotation would also have relocated rear damage, not
erased it, while the bench premise (the dummy faces its attacker) was
assumed, never measured.

The zero-premise probe (BT_ASPECT_TEST): four self-impacts at known
WORLD cardinals + one at each weapon's PHYSICAL MUZZLE position -- the
mech's own asymmetric geometry as the left/right anchor. Measured:

* WorldToLocal is a clean R(yaw), no hidden terms (yaws -30/150/40 deg
  all consistent);
* our frame: RIGHT = +X -- SAME as the 1995 ring (W0/W7 = Right*) --
  and FORWARD = -Z, flipped vs the ring's Front*-in-+Z-arc;
* under the pi rotation the pods CROSSED (left muzzle -> rtorso);
  under z-negation every anchor lands its own side.

So: negate local z only, and -- since a reflection reverses angular
direction -- the SelectSlice torso-twist term flips sign with it
(twist was 0 in all probes; twisted-torso verify tracked on #124).

Anchor acceptance (fresh exe, third yaw): LRM15_1 left pod -> ltorso,
LRM15_2 -> right wedges, left/right arm muzzles -> larm/rarm, nose ->
front cells, tail -> rear cells, flank cardinals -> rgun / left wedges.

The BT_ASPECT_TEST probe + BTWeaponMuzzleWorld bridge stay as bench
scalpels.

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

game/reconstructed/mechweap.cpp

@@ -997,3 +997,13 @@ void BTWeaponSetViewFireEnable(Subsystem *sub, int enable)
 	if (sub != 0 && sub->IsDerivedFrom(MechWeapon::ClassDerivations))
 		((MechWeapon *)sub)->SetViewFireEnable(enable);
 }
+
+// #124 aspect probe: a weapon's physical muzzle WORLD position (the pod's own
+// asymmetric geometry as a left/right anchor).  -1-family returns 0.
+int BTWeaponMuzzleWorld(Subsystem *sub, Point3D *out)
+{
+	if (sub == 0 || out == 0 || !sub->IsDerivedFrom(MechWeapon::ClassDerivations))
+		return 0;
+	((MechWeapon *)sub)->MuzzlePoint(*out);		// the public beam-render alias
+	return 1;
+}