feat: 집기/놓기 상호작용 (게임 핵심 루프)

- Carryable: 집을 수 있는 물건 표시
- PickupController: 범위 내 박스를 E키로 집고/놓기 + 화면 힌트
- PickupDemoSetup: 플레이어에 PickupController 부착 + 입고 박스 4개 스폰

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Assets/Scripts/Gameplay/Carryable.cs

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+using UnityEngine;
+
+namespace SinoWms.Gameplay
+{
+    /// <summary>플레이어가 집어 옮길 수 있는 물건(박스/팔레트) 표시 컴포넌트.</summary>
+    [RequireComponent(typeof(Rigidbody))]
+    [RequireComponent(typeof(Collider))]
+    public class Carryable : MonoBehaviour
+    {
+        [Tooltip("힌트/로그에 표시할 이름. 비우면 오브젝트 이름 사용.")]
+        public string displayName;
+
+        public string Label => string.IsNullOrEmpty(displayName) ? name : displayName;
+    }
+}

Assets/Scripts/Gameplay/Carryable.cs.meta

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+fileFormatVersion: 2
+guid: 315a7e23f649b4187a444b01f14a8e9d

Assets/Scripts/Gameplay/PickupController.cs

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+using UnityEngine;
+using UnityEngine.InputSystem;
+using SinoWms.Gameplay;
+
+namespace SinoWms.Player
+{
+    /// <summary>
+    /// 캐릭터의 집기/놓기 상호작용. 범위 내 가장 가까운 Carryable을 E키로 집어
+    /// 앞쪽 홀드 포인트에 들고 다니고, 다시 E키로 내려놓는다.
+    /// </summary>
+    public class PickupController : MonoBehaviour
+    {
+        [SerializeField] private float pickupRange = 2.5f;
+        [SerializeField] private Transform holdPoint;
+
+        private Carryable _carried;
+        private Carryable _target;       // 현재 집을 수 있는 후보(힌트 표시용)
+        private GUIStyle _style;
+
+        private void Awake()
+        {
+            if (holdPoint == null)
+            {
+                var hp = new GameObject("HoldPoint").transform;
+                hp.SetParent(transform, false);
+                hp.localPosition = new Vector3(0f, 0.6f, 0.9f);
+                holdPoint = hp;
+            }
+        }
+
+        private void Update()
+        {
+            var kb = Keyboard.current;
+            if (kb == null) return;
+
+            if (_carried == null)
+                _target = FindNearest();
+
+            if (kb.eKey.wasPressedThisFrame)
+            {
+                if (_carried != null) Drop();
+                else if (_target != null) PickUp(_target);
+            }
+        }
+
+        private Carryable FindNearest()
+        {
+            var hits = Physics.OverlapSphere(transform.position, pickupRange);
+            Carryable best = null;
+            float bestDist = float.MaxValue;
+            foreach (var h in hits)
+            {
+                var c = h.GetComponentInParent<Carryable>();
+                if (c == null || c == _carried) continue;
+                float d = Vector3.Distance(transform.position, c.transform.position);
+                if (d < bestDist) { bestDist = d; best = c; }
+            }
+            return best;
+        }
+
+        private void PickUp(Carryable c)
+        {
+            _carried = c;
+            _target = null;
+
+            if (c.TryGetComponent<Rigidbody>(out var rb)) rb.isKinematic = true;
+            if (c.TryGetComponent<Collider>(out var col)) col.enabled = false;
+
+            c.transform.SetParent(holdPoint);
+            c.transform.localPosition = Vector3.zero;
+            c.transform.localRotation = Quaternion.identity;
+        }
+
+        private void Drop()
+        {
+            var c = _carried;
+            _carried = null;
+
+            c.transform.SetParent(null);
+            c.transform.position = holdPoint.position;
+            c.transform.rotation = holdPoint.rotation;
+
+            if (c.TryGetComponent<Collider>(out var col)) col.enabled = true;
+            if (c.TryGetComponent<Rigidbody>(out var rb)) rb.isKinematic = false;
+        }
+
+        private void OnGUI()
+        {
+            _style ??= new GUIStyle(GUI.skin.box) { fontSize = 18, alignment = TextAnchor.MiddleCenter };
+
+            string msg = null;
+            if (_carried != null) msg = $"E: 내려놓기 — {_carried.Label}";
+            else if (_target != null) msg = $"E: 집기 — {_target.Label}";
+            if (msg == null) return;
+
+            GUI.Label(new Rect(Screen.width / 2f - 150f, 24f, 300f, 32f), msg, _style);
+        }
+    }
+}

Assets/Scripts/Gameplay/PickupController.cs.meta

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+fileFormatVersion: 2
+guid: 8525e0c0e962c47b78e49a7e3371fe97