feat: 플레이어 다운 및 넉백 피격 반응 추가

- HitReactionController로 다운과 넉백 전용 로직을 분리
- 다운 시작, 루프, 회복 애니메이션과 DownEffect를 연결
- 행동 상태와 스킬 취소가 피격 반응과 연동되도록 정리
- 자동 검증 러너에 다운 및 넉백 검증을 추가

Assets/_Game/Scripts/Player/PlayerMovement.cs

@@ -34,6 +34,8 @@ namespace Colosseum.Player
         private InputSystem_Actions inputActions;
         private bool isJumping;
         private bool wasGrounded;
+        private Vector3 forcedMovementVelocity;
+        private float forcedMovementRemaining;
 
         // 클라이언트가 기록, 서버가 소비하는 월드 스페이스 이동 방향
         private NetworkVariable<Vector2> netMoveInput = new NetworkVariable<Vector2>(
@@ -48,6 +50,7 @@ namespace Colosseum.Player
         public float CurrentMoveSpeed => netMoveInput.Value.magnitude * moveSpeed * GetMoveSpeedMultiplier();
         public bool IsGrounded => characterController != null ? characterController.isGrounded : false;
         public bool IsJumping => isJumping;
+        public bool IsForcedMoving => forcedMovementRemaining > 0f && forcedMovementVelocity.sqrMagnitude > 0.0001f;
 
         public override void OnNetworkSpawn()
         {
@@ -115,6 +118,7 @@ namespace Colosseum.Player
         {
             CleanupInputActions();
             moveInput = Vector2.zero;
+            ClearForcedMovement();
         }
 
         private void OnEnable()
@@ -143,6 +147,7 @@ namespace Colosseum.Player
         public override void OnNetworkDespawn()
         {
             CleanupInputActions();
+            ClearForcedMovement();
         }
 
         private void OnMovePerformed(InputAction.CallbackContext context) => moveInput = context.ReadValue<Vector2>();
@@ -259,10 +264,12 @@ namespace Colosseum.Player
         {
             if (characterController == null) return;
 
+            Vector3 forcedDelta = ConsumeForcedMovementDelta(Time.deltaTime);
+
             if (skillController != null && skillController.IsPlayingAnimation)
             {
                 if (!skillController.UsesRootMotion)
-                    characterController.Move(velocity * Time.deltaTime);
+                    characterController.Move(velocity * Time.deltaTime + forcedDelta);
                 return;
             }
 
@@ -278,7 +285,7 @@ namespace Colosseum.Player
                 moveDirection = Vector3.zero;
 
             float actualMoveSpeed = moveSpeed * GetMoveSpeedMultiplier();
-            characterController.Move((moveDirection * actualMoveSpeed + velocity) * Time.deltaTime);
+            characterController.Move((moveDirection * actualMoveSpeed + velocity) * Time.deltaTime + forcedDelta);
 
             if (moveDirection != Vector3.zero)
             {
@@ -323,6 +330,33 @@ namespace Colosseum.Player
             return actionState.MoveSpeedMultiplier;
         }
 
+        /// <summary>
+        /// 넉백처럼 입력과 무관한 강제 이동을 적용합니다.
+        /// </summary>
+        public void ApplyForcedMovement(Vector3 worldVelocity, float duration)
+        {
+            if (!IsServer)
+                return;
+
+            if (duration <= 0f || worldVelocity.sqrMagnitude <= 0.0001f)
+            {
+                ClearForcedMovement();
+                return;
+            }
+
+            forcedMovementVelocity = worldVelocity;
+            forcedMovementRemaining = duration;
+        }
+
+        /// <summary>
+        /// 강제 이동 상태를 즉시 초기화합니다.
+        /// </summary>
+        public void ClearForcedMovement()
+        {
+            forcedMovementVelocity = Vector3.zero;
+            forcedMovementRemaining = 0f;
+        }
+
         private PlayerActionState GetOrCreateActionState()
         {
             var foundState = GetComponent<PlayerActionState>();
@@ -343,6 +377,7 @@ namespace Colosseum.Player
             if (!skillController.UsesRootMotion) return;
 
             Vector3 deltaPosition = animator.deltaPosition;
+            Vector3 forcedDelta = ConsumeForcedMovementDelta(Time.deltaTime);
 
             if (blockedDirection != Vector3.zero)
             {
@@ -357,11 +392,11 @@ namespace Colosseum.Player
             if (skillController.IgnoreRootMotionY)
             {
                 deltaPosition.y = 0f;
-                characterController.Move(deltaPosition + velocity * Time.deltaTime);
+                characterController.Move(deltaPosition + velocity * Time.deltaTime + forcedDelta);
             }
             else
             {
-                characterController.Move(deltaPosition);
+                characterController.Move(deltaPosition + forcedDelta);
             }
 
             if (animator.deltaRotation != Quaternion.identity)
@@ -372,5 +407,22 @@ namespace Colosseum.Player
 
             wasGrounded = characterController.isGrounded;
         }
+
+        private Vector3 ConsumeForcedMovementDelta(float deltaTime)
+        {
+            if (forcedMovementRemaining <= 0f || forcedMovementVelocity.sqrMagnitude <= 0.0001f)
+                return Vector3.zero;
+
+            float appliedDeltaTime = Mathf.Min(deltaTime, forcedMovementRemaining);
+            forcedMovementRemaining = Mathf.Max(0f, forcedMovementRemaining - appliedDeltaTime);
+
+            Vector3 delta = forcedMovementVelocity * appliedDeltaTime;
+            if (forcedMovementRemaining <= 0f)
+            {
+                forcedMovementVelocity = Vector3.zero;
+            }
+
+            return delta;
+        }
     }
 }