MP: the Mech-level update records @0x4a0c2c/@0x4a1232 -- all 9 types byte-exact (task #1)

- Writer transcribed from the recovered disasm; reader rewritten from
  part_012.c with every Wword absorber promoted to named engine/port members
  (updateOrigin/updateVelocity/projectedOrigin/projectedVelocity/nextUpdate/
  lastUpdate + bodyTargetSpeed/latches/alarms).  Wire sizes verified live:
  0x14/0x20/0x2c/0x78.
- movementMode UNIFIED with Simulation::simulationState (binary mech+0x40 =
  StateIndicator@0x2c currentState) -- death/limbo/airborne now replicate in
  every record header.  Three mislabels of the same binary fns retired:
  SetInstanceFlags + RequestActionFlags -> Mech::ForceUpdate (updateModel |=
  mask, 0xfe03 disabled filter); IsNetworkCopy -> IsDisabled.
- Senders wired byte-exact: gait transitions Force(8), knockdown Force(1|0x20),
  death Force(1|0x40), Reset Force(0x1f) + binary zero-set, perf-loop
  deadbands (speed type 2, orientation type 4, heat type 7).
- 2-node verified: types 2/3/4 flow while driving; kill -> type-6 record
  (simState=9) -> the OBSERVER's replicant runs the wreck sink loop with no
  double death transition; respawn 0x1f burst snaps + un-wrecks the peer;
  walking replicant un-regressed (run 12, cycle tracking); solo clean.

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

game/reconstructed/mechmppr.cpp

@@ -1233,3 +1233,19 @@ void *BTResolveRosterPilot(int slot)
 	}
 	return (void *)mapper->GetPilot(slot);						// FUN_004b0898
 }
+
+//###########################################################################
+//					BTMapperSpeedDemand -- complete-type bridge (task #1)
+//
+//	Mech::WriteUpdateRecord stamps the controls mapper's live speedDemand
+//	(binary: *(subsystemArray[0] + 0x128)) into every record tail.  mech.cpp
+//	sees only the forward declaration of MechControlsMapper, so the read
+//	lives here in the complete-type TU (the house databinding pattern).
+//
+Scalar BTMapperSpeedDemandRaw(void *mapper)
+{
+	// void* signature: mech.cpp's TU carries a local recon stub type under the
+	// same name, so a typed signature mangles differently there (class/struct
+	// + type identity).  The cast happens HERE, in the complete-type TU.
+	return (mapper != 0) ? ((MechControlsMapper *)mapper)->speedDemand : Scalar(0.0f);
+}