MP task #47: DISPROVE the Entity-layout root cause; correct the record

The prior commit (c78662a) filed cross-pod damage failure under a
"cross-TU Entity/EntityID layout divergence" (and the P5 base-region
audit). A compile-time offsetof probe injected into BOTH translation
units disproves that: game/reconstructed AND engine/MUNGA compute an
IDENTICAL Entity layout --

  sizeof(Entity)=444  offsetof(entityID)=380 (0x17C)
  offsetof(ownerID)=388  offsetof(simulationFlags)=32
  offsetof(Mech,entityID)=380  (Entity subobject at 0)

So Entity::Dispatch reads this->entityID at the SAME offset mech4's
GetEntityID() does -- there is no per-TU read difference, and the
logged 3:22 (mech4 candidate) vs 3:19 (engine Dispatch) cannot be one
object read two ways. Those lines were different objects/messages,
mis-correlated. The distinct, REAL P5 "base-region layout divergence"
(HARD_PROBLEMS.md) is about raw-offset stomps at this+0x2d4..0x2f0 --
far above entityID -- and is unrelated to #47.

Changes:
- Revert the committed BT_MP_NET engine diagnostics (ENTITY/EVENT/
  NTTMGR/RECEIVER/L4NET) to the clean a9c3e96 baseline -- those are
  the very instruments that produced the mis-correlated data.
- mech4 BT_MP_FORCE_DMG hook: dispatch via the real m->Dispatch(&td)
  path (no false id stamping); comment records the offsetof finding.
- context/multiplayer.md: layout-divergence RULED OUT; 3:22/3:19 marked
  unconfirmed; leading hypotheses reframed as H2 (wire host-relative
  (de)serialization) vs H3 (replicant id != master's registered key),
  to be distinguished by a 2-node run with per-message correlation.

Solo un-regressed (mech walks + targets, 0 faults). Cross-pod delivery
remains open, but the investigation is redirected off the wrong (large,
structural) layout-audit path onto the EntityID wire/id-assignment path.

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

engine/MUNGA/ENTITY.cpp

@@ -241,13 +241,6 @@ void
 	// If this is a replicant instance, reroute the message to the master
 	//-------------------------------------------------------------------
 	//
-	if (getenv("BT_MP_NET") && message->messageID != 6)
-		DEBUG_STREAM << "[mp-disp] Entity::Dispatch msgID=" << (int)message->messageID
-			<< " inst=" << (int)GetInstance()
-			<< (GetInstance() == ReplicantInstance ? "  REPLICANT -> reroute to master"
-			 : (IsValid() ? "  master/valid -> local Receive" : "  INVALID -> Post"))
-			<< "\n" << std::flush;
-
 	if (GetInstance() == ReplicantInstance)
 	{
 		application->SendMessage(