feat(review): deterministic walking capture, and the defect it exposed

The shot actor can now photograph a moving pawn: a per-shot ShotFollow flag re-places
the camera every frame at a fixed offset in the pawn's frame, and the walk is driven
per shot (SetReviewWalk) with the pawn returned to spawn after a follow shot, so the
fixed-camera shots later in the list still find it in place. With that, the capture
stopped depending on where a 4.5 m/s pawn happened to be.

Two further bugs fixed on the way:
- the engine's screenshot folder is cleared before each run. The collect step copies
  every review-*.png it finds in Saved/, so a shot retired from the camera list kept
  reappearing with byte-identical content from an older run - which is how a walk shot
  that was never captured looked like a captured one.
- UpdateBodyAnimation no longer calls SetAnimation every frame. Re-setting the same
  clip restarts it, which freezes the body on frame 0.

What the deterministic capture then exposed: the walk clip is applied but does not
advance - every walking frame shows the same pose (arms forward, legs together). The
stride shot is retired again rather than shipped, and TODO.md names the next step:
log GetCurrentAssetTime across frames and check the imported PlayRate. The harness
stays wired for when the clip plays.

Shots 6 and 7 were re-rendered after these changes and still pass; 7/7 verify.

Game/GigLine/Source/GigLine/GigLineShotActor.cpp

@@ -1,5 +1,8 @@
 #include "GigLineShotActor.h"
 
+#include "GigLineCharacter.h"
+#include "Kismet/GameplayStatics.h"
+
 #include "Camera/CameraActor.h"
 #include "Camera/CameraComponent.h"
 #include "Engine/World.h"
@@ -32,6 +35,12 @@ void AGigLineShotActor::Tick(float DeltaSeconds)
 
 	if (bWaitingForSettle)
 	{
+		// A follow shot tracks the pawn while it settles, otherwise the subject
+		// walks out of the frame between placement and capture.
+		if (CurrentShot < ShotFollow.Num() && ShotFollow[CurrentShot])
+		{
+			UpdateFollowCamera();
+		}
 		SettleCountdown -= DeltaSeconds;
 		if (SettleCountdown <= 0.f)
 		{
@@ -53,11 +62,40 @@ void AGigLineShotActor::Tick(float DeltaSeconds)
 	{
 		bWaitingForScreenshot = false;
 		UE_LOG(LogTemp, Log, TEXT("GigLineShotActor: captured %s"), *FScreenshotRequest::GetFilename());
+		// Walking shots move the pawn; put it back before the fixed-camera shots run.
+		if (ShotFollow.IsValidIndex(CurrentShot) && ShotFollow[CurrentShot])
+		{
+			if (AGigLineCharacter* Character = Cast<AGigLineCharacter>(UGameplayStatics::GetPlayerPawn(this, 0)))
+			{
+				Character->ReturnToStartForReview();
+			}
+		}
 		++CurrentShot;
 		NextShot();
 	}
 }
 
+void AGigLineShotActor::UpdateFollowCamera()
+{
+	if (!CurrentCamera)
+	{
+		return;
+	}
+	const APawn* Pawn = UGameplayStatics::GetPlayerPawn(this, 0);
+	if (!Pawn)
+	{
+		return;
+	}
+	// Offset in the pawn's frame: to its right, slightly above, looking at the
+	// pelvis. Right-of-pawn gives a profile view, which is where a stride reads.
+	const FVector Right = Pawn->GetActorRightVector();
+	const FVector Origin = Pawn->GetActorLocation();
+	const FVector CameraLocation = Origin + Right * 420.f + FVector(0.f, 0.f, 90.f);
+	const FVector Target = Origin + FVector(0.f, 0.f, 40.f);
+	CurrentCamera->SetActorLocation(CameraLocation);
+	CurrentCamera->SetActorRotation((Target - CameraLocation).Rotation());
+}
+
 void AGigLineShotActor::NextShot()
 {
 	if (!PlayerController)
@@ -93,6 +131,20 @@ void AGigLineShotActor::NextShot()
 			Cam->SetFieldOfView(ShotFieldOfView[CurrentShot]);
 		}
 	}
+	// Follow shots ignore their recorded transform after this point: the camera is
+	// rebuilt from the pawn every frame until the capture. They also own the walking:
+	// the pawn only holds forward input while a follow shot is being taken, so the
+	// fixed-camera shots later in the list still find it at the spawn point.
+	const bool bFollowThisShot = ShotFollow.IsValidIndex(CurrentShot) && ShotFollow[CurrentShot];
+	if (AGigLineCharacter* Character = Cast<AGigLineCharacter>(UGameplayStatics::GetPlayerPawn(this, 0)))
+	{
+		Character->SetReviewWalk(bFollowThisShot);
+	}
+	if (bFollowThisShot)
+	{
+		UpdateFollowCamera();
+	}
+
 	PlayerController->SetViewTarget(CurrentCamera);
 
 	SettleCountdown = SettleSeconds;