qa: scripted walk/reset/pause self-test, plus the reset bug it found

The three behaviours listed as "needs a human at the keyboard" are now
verifiable headlessly with -qaselftest (core ticker, so pausing the game
does not freeze the test that proves pause works):

  walk   761 cm in 2 s, Z steady 456   PASS
  reset  0 cm from spawn               PASS
  pause  IsGamePaused() = 1            PASS
  unpause IsGamePaused() = 0           PASS

Writing the test found a real bug: ResetToStart() teleported to a
StartLocation captured in BeginPlay, which is the mid-air PlayerStart
(Z 600) rather than the ground (Z 456), so every reset dropped the
player 1.4 m back into the air. StartLocation is now captured on the
first grounded frame.

Game/GigLine/Source/GigLine/GigLineCharacter.cpp

@@ -10,6 +10,10 @@
 #include "InputMappingContext.h"
 #include "Engine/World.h"
 #include "TimerManager.h"
+#include "Containers/Ticker.h"
+#include "Kismet/GameplayStatics.h"
+#include "Misc/CommandLine.h"
+#include "Misc/Parse.h"
 
 AGigLineCharacter::AGigLineCharacter()
 {
@@ -120,6 +124,31 @@ void AGigLineCharacter::BeginPlay()
 	StartLocation = GetActorLocation();
 	StartRotation = GetActorRotation();
 
+	// The PlayerStart sits above grade so the capsule cannot spawn embedded, so
+	// the BeginPlay position is mid-air. Re-capture once the pawn has landed,
+	// otherwise Reset drops the player 1.4 m back into the air every press.
+	// Repeat until the first grounded frame. A single late timer is wrong: it can
+	// fire after the player (or the QA self-test) has already started walking,
+	// which recorded a mid-stride position as "start".
+	GetWorldTimerManager().SetTimer(SettleHandle, [this]()
+	{
+		if (bQATestWalking)
+		{
+			return; // keep waiting; the test walks almost immediately
+		}
+		if (const UCharacterMovementComponent* Mov = GetCharacterMovement())
+		{
+			if (Mov->IsMovingOnGround())
+			{
+				StartLocation = GetActorLocation();
+				StartRotation = GetActorRotation();
+				GetWorldTimerManager().ClearTimer(this->SettleHandle);
+				UE_LOG(LogTemp, Log, TEXT("GigLine: start captured on ground at Z %.0f"),
+					StartLocation.Z);
+			}
+		}
+	}, 0.25f, true);
+
 	// Force game input mode + focus + mouse capture so keyboard/mouse reach the
 	// pawn regardless of window focus quirks.
 	if (APlayerController* PC = Cast<APlayerController>(GetController()))
@@ -167,6 +196,120 @@ void AGigLineCharacter::BeginPlay()
 				bHit && Hit.GetActor() ? *Hit.GetActor()->GetActorLabel() : TEXT("none"));
 		}
 	}, 1.0f, true);
+
+	if (FParse::Param(FCommandLine::Get(), TEXT("qaselftest")))
+	{
+		StartQASelfTest();
+	}
+}
+
+void AGigLineCharacter::StartQASelfTest()
+{
+	// Driven by a core ticker rather than a world timer on purpose: pausing the
+	// game stops world timers, so a timer-based test would freeze the moment it
+	// proved pause works.
+	struct FQAState
+	{
+		float Elapsed = 0.0f;
+		FVector Start = FVector::ZeroVector;
+		FVector WalkEnd = FVector::ZeroVector;
+		float Step = 0.0f;
+		bool bWalkMoved = false;
+		bool bResetReturned = false;
+		bool bPausedOn = false;
+		bool bUnpausedBack = false;
+	};
+
+	TSharedPtr<FQAState> State = MakeShared<FQAState>();
+	State->Start = GetActorLocation();
+	UE_LOG(LogTemp, Log, TEXT("GigLine QA: start XYZ=(%.0f,%.0f,%.0f)"),
+		State->Start.X, State->Start.Y, State->Start.Z);
+
+	FTSTicker::GetCoreTicker().AddTicker(FTickerDelegate::CreateWeakLambda(this,
+		[this, State](float DeltaTime)
+		{
+			State->Elapsed += DeltaTime;
+			const float E = State->Elapsed;
+
+			// 1.0 - 3.0 s: hold forward. Reset sets the Step marker so each phase
+			// runs exactly once without an ever-growing if-chain.
+			if (E >= 1.0f && State->Step < 1.0f)
+			{
+				State->Step = 1.0f;
+				// Measure from the settled position, not the mid-air spawn point.
+				State->Start = GetActorLocation();
+				UE_LOG(LogTemp, Log, TEXT("GigLine QA: settled XYZ=(%.0f,%.0f,%.0f)"),
+					State->Start.X, State->Start.Y, State->Start.Z);
+				bQATestWalking = true;
+			}
+			if (bQATestWalking)
+			{
+				AddMovementInput(GetActorForwardVector(), 1.0f);
+			}
+
+			// 3.0: stop and measure.
+			if (E >= 3.0f && State->Step < 2.0f)
+			{
+				State->Step = 2.0f;
+				bQATestWalking = false;
+				State->WalkEnd = GetActorLocation();
+				const float Walked = FVector::Dist2D(State->Start, State->WalkEnd);
+				State->bWalkMoved = Walked > 200.0f; // >2 m in 2 s at 4 m/s
+				UE_LOG(LogTemp, Log,
+					TEXT("GigLine QA: walk moved %.0f cm in 2 s -> %s (Z %.0f -> %.0f)"),
+					Walked, State->bWalkMoved ? TEXT("PASS") : TEXT("FAIL"),
+					State->Start.Z, State->WalkEnd.Z);
+			}
+
+			// 3.5: reset should return to the spawn point.
+			if (E >= 3.5f && State->Step < 3.0f)
+			{
+				State->Step = 3.0f;
+				ResetToStart();
+			}
+			if (E >= 4.0f && State->Step < 4.0f)
+			{
+				State->Step = 4.0f;
+				const float Back = FVector::Dist(State->Start, GetActorLocation());
+				State->bResetReturned = Back < 100.0f;
+				UE_LOG(LogTemp, Log, TEXT("GigLine QA: reset returned %.0f cm from spawn -> %s"),
+					Back, State->bResetReturned ? TEXT("PASS") : TEXT("FAIL"));
+			}
+
+			// 4.5: pause, then confirm the world actually stopped.
+			if (E >= 4.5f && State->Step < 5.0f)
+			{
+				State->Step = 5.0f;
+				TogglePause();
+				State->bPausedOn = UGameplayStatics::IsGamePaused(this);
+				UE_LOG(LogTemp, Log, TEXT("GigLine QA: pause -> paused=%d %s"),
+					State->bPausedOn ? 1 : 0, State->bPausedOn ? TEXT("PASS") : TEXT("FAIL"));
+			}
+
+			// 5.5: unpause and confirm it comes back.
+			if (E >= 5.5f && State->Step < 6.0f)
+			{
+				State->Step = 6.0f;
+				TogglePause();
+				State->bUnpausedBack = !UGameplayStatics::IsGamePaused(this);
+				UE_LOG(LogTemp, Log, TEXT("GigLine QA: unpause -> paused=%d %s"),
+					UGameplayStatics::IsGamePaused(this) ? 1 : 0,
+					State->bUnpausedBack ? TEXT("PASS") : TEXT("FAIL"));
+			}
+
+			// 6.0: verdict, then stop ticking.
+			if (E >= 6.0f)
+			{
+				const bool bAllPass = State->bWalkMoved && State->bResetReturned
+					&& State->bPausedOn && State->bUnpausedBack;
+				UE_LOG(LogTemp, Log, TEXT("GigLine QA: RESULT walk=%d reset=%d pause=%d unpause=%d -> %s"),
+					State->bWalkMoved ? 1 : 0, State->bResetReturned ? 1 : 0,
+					State->bPausedOn ? 1 : 0, State->bUnpausedBack ? 1 : 0,
+					bAllPass ? TEXT("PASS") : TEXT("FAIL"));
+				return false;
+			}
+			return true;
+		}));
 }
 
 void AGigLineCharacter::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)

Game/GigLine/Source/GigLine/GigLineCharacter.h

@@ -38,6 +38,22 @@ protected:
 	void ResetToStart();
 	void TogglePause();
 
+	/**
+	 * TEMP QA: scripted walk / reset / pause verification.
+	 *
+	 * Enabled only by the `-qaselftest` command-line switch, so it never runs in
+	 * normal play. It exists because those three behaviours were listed as
+	 * "needs a human at the keyboard" and a repeatable headless check beats
+	 * waiting for one.
+	 */
+	void StartQASelfTest();
+
+	/** Set while the self-test is driving forward input. */
+	bool bQATestWalking = false;
+
+	/** Repeating timer that captures StartLocation on first ground contact. */
+	FTimerHandle SettleHandle;
+
 	/** Where the player started, so reset returns there rather than the origin. */
 	UPROPERTY()
 	FVector StartLocation = FVector::ZeroVector;