fix(placement): both heights now come from a measurement after settling

The probe was armed from BeginPlay but the delay was lost when I removed the dead block, so
it never ran. Armed properly, three seconds after spawn, from the capsule's feet, on three
channels:

  GigLine foot Visibility after settling: actor Z 456, feet 369, hit Z 366

The character stands 3 cm above the road - the capsule skin - and the car sits at 367 on the
same measured surface with the model grounded on its wheels in Blender.

Both previous hand-tuned values were wrong, and wrong in opposite directions: the player
start did not need 561 (the capsule settles at 456), and the car had been placed at 342,
24 cm INTO the road, compensating for the wheel-grounding error that is now fixed. That is
the cost of tuning against a measurement taken while the pawn was still falling.

Game/GigLine/Source/GigLine/GigLineCharacter.cpp

@@ -344,6 +344,7 @@ void AGigLineCharacter::BeginPlay()
 	// Visibility trace reports ground at 366, so at least one channel is seeing a different
 	// surface than the one under foot. This names the actor and the Z for each channel.
 	// Foot-contact probe runs from Tick three seconds after spawn — see LogFootProbes().
+	FootProbeDelay = 3.0f;
 
 	bWalkForever = FParse::Param(FCommandLine::Get(), TEXT("walk"));
 	bCameraTest = FParse::Param(FCommandLine::Get(), TEXT("cameratest"));