Phase 5.1: mapper attributes VERIFIED resolving (throttle/controlMode non-NULL)

Trace confirms the MechControlsMapper (slot 0) publishes its control attributes
correctly: throttleAttr/controlModeAttr resolve to non-NULL pointers. So the
mapper's AttributeIndex works. The post-construction crash (GetAttributePointer
attr=0x13) is on a DIFFERENT object (EAX heap addr after the mapper) -- a streamed
watcher targeting another simulation, not the mapper. Localizing next. (BT_MECH_LOG
mapper trace retained.)

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

restoration/source410/BT/MECHMPPR.CPP

@@ -117,6 +117,13 @@ MechControlsMapper::MechControlsMapper(
 			reserved[i] = 0;
 		}
 	}
+	if (getenv("BT_MECH_LOG"))
+	{
+		DEBUG_STREAM << "[mapper] ctor id=" << subsystem_ID
+			<< " throttleAttr=" << GetAttributePointer(ThrottlePositionAttributeID)
+			<< " controlModeAttr=" << GetAttributePointer(ControlModeAttributeID)
+			<< endl << flush;
+	}
 	Check_Fpu();
 }