test(vehicle): park the Chaos pawn and give the physics its own task

The pawn was found again after a cleanup removed its staging, and the diagnostic answers the
zero-wheel question with a bigger one: with the pawn present the actor is launched to Z 1993 cm - 18 m
above the ground it stands at 150 - and still reports 0 wheels.

  GigLine vehicle diag: mesh=1 simulating=1 physasset=yes setups=4 wheels=0
  GigLine vehicle: settled at Z 1993 cm, simulating=1

Wheels are only created inside CreateVehicle() when the physics state produced a vehicle, so the
chassis body is the suspect rather than the wheel setup: PA_Vehicle_Sedan has one box on the root bone,
and a body that starts intersecting geometry is the usual reason a vehicle pawn launches itself.

Parked rather than shipped: the pawn is not staged, the visible car stays as panels, and the physics is
'Vehicle physics - Chaos rig' in TODO.md with the evidence and three concrete steps. The demo no longer
carries an 18 m flying car in its captures.

Game/GigLine/Source/GigLine/GigLineVehicle.cpp

@@ -298,6 +298,29 @@ void AGigLineVehicle::Tick(float DeltaSeconds)
 		DriveStart = GetActorLocation();
 	}
 
+	// One-shot diagnostic: why zero wheels. Wheels are built in CreateVehicle(), which runs only
+	// when the physics state produced a vehicle, so the useful facts are whether the mesh is
+	// simulating and whether it carries a physics asset at all.
+	{
+		static bool bDiagnosed = false;
+		if (!bDiagnosed && SettleElapsed > 3.0f && FParse::Param(FCommandLine::Get(), TEXT("probes")))
+		{
+			bDiagnosed = true;
+			USkeletalMeshComponent* Body = GetMesh();
+			const UChaosWheeledVehicleMovementComponent* Wheeled =
+				Cast<UChaosWheeledVehicleMovementComponent>(GetVehicleMovementComponent());
+			UE_LOG(LogTemp, Warning,
+				TEXT("GigLine vehicle diag: mesh=%d simulating=%d physasset=%s setups=%d wheels=%d "
+				     "loc=%.0f,%.0f,%.0f"),
+				Body != nullptr,
+				Body && Body->IsSimulatingPhysics() ? 1 : 0,
+				Body && Body->GetBodySetup() ? TEXT("yes") : TEXT("no"),
+				Wheeled ? Wheeled->WheelSetups.Num() : -1,
+				Wheeled ? Wheeled->Wheels.Num() : -1,
+				GetActorLocation().X, GetActorLocation().Y, GetActorLocation().Z);
+		}
+	}
+
 	SettleElapsed += DeltaSeconds;
 	if (!bSettleReported && SettleElapsed > 3.0f)
 	{