feat: 카메라-플레이어 사이 장애물 숨김 처리

- SphereCast 충돌 당기기 로직 제거로 카메라가 항상 원래 거리 유지
- ObstacleTransparencyController 신규: 카메라-타겟 사이 장애물을 renderer.enabled로 숨김
- 플레이어 발 위치 이하의 바닥/지형은 숨김 대상에서 제외
- 파티클/트레일 렌더러는 숨김 스킵

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Assets/_Game/Scripts/Player/ObstacleTransparencyController.cs

@@ -0,0 +1,105 @@
+using System.Collections.Generic;
+
+using UnityEngine;
+
+namespace Colosseum.Player
+{
+    /// <summary>
+    /// 카메라와 타겟 사이의 장애물을 숨기는 컨트롤러
+    /// </summary>
+    public class ObstacleTransparencyController : MonoBehaviour
+    {
+        [Header("Occlusion Settings")]
+        [Min(0.01f)] [SerializeField] private float checkRadius = 0.3f;
+
+        private Transform cameraTransform;
+        private Transform targetTransform;
+        private LayerMask occlusionMask;
+        private readonly HashSet<Renderer> hiddenRenderers = new();
+
+        public void Initialize(Transform target, LayerMask mask)
+        {
+            cameraTransform = GetComponent<Camera>().transform;
+            targetTransform = target;
+            occlusionMask = mask;
+        }
+
+        private void LateUpdate()
+        {
+            if (cameraTransform == null || targetTransform == null) return;
+
+            Vector3 origin = cameraTransform.position;
+            Vector3 direction = targetTransform.position - origin;
+            float maxDistance = direction.magnitude;
+
+            if (maxDistance < 0.01f) return;
+
+            direction.Normalize();
+
+            HashSet<Renderer> currentHits = CollectHits(origin, direction, maxDistance);
+
+            foreach (Renderer renderer in currentHits)
+            {
+                if (!hiddenRenderers.Contains(renderer))
+                {
+                    renderer.enabled = false;
+                    hiddenRenderers.Add(renderer);
+                }
+            }
+
+            List<Renderer> toShow = null;
+            foreach (Renderer renderer in hiddenRenderers)
+            {
+                if (renderer == null || !currentHits.Contains(renderer))
+                {
+                    if (renderer != null)
+                        renderer.enabled = true;
+                    (toShow ??= new List<Renderer>()).Add(renderer);
+                }
+            }
+
+            if (toShow != null)
+            {
+                foreach (Renderer renderer in toShow)
+                    hiddenRenderers.Remove(renderer);
+            }
+        }
+
+        private HashSet<Renderer> CollectHits(Vector3 origin, Vector3 direction, float maxDistance)
+        {
+            var hits = new HashSet<Renderer>();
+            RaycastHit[] rayHits = Physics.SphereCastAll(origin, checkRadius, direction, maxDistance, occlusionMask, QueryTriggerInteraction.Ignore);
+
+            float targetY = targetTransform.position.y;
+
+            foreach (RaycastHit hit in rayHits)
+            {
+                if (hit.point.y <= targetY) continue;
+
+                Renderer renderer = hit.collider.GetComponent<Renderer>();
+                if (renderer == null) continue;
+                if (renderer is ParticleSystemRenderer || renderer is TrailRenderer) continue;
+
+                hits.Add(renderer);
+            }
+
+            return hits;
+        }
+
+        public void ClearHidden()
+        {
+            foreach (Renderer renderer in hiddenRenderers)
+            {
+                if (renderer != null)
+                    renderer.enabled = true;
+            }
+
+            hiddenRenderers.Clear();
+        }
+
+        private void OnDestroy()
+        {
+            ClearHidden();
+        }
+    }
+}