Feat: 배경 씬 웹 업로드 제외 기능 추가

- BackgroundSceneInfo에 excludeFromWeb 플래그 추가
- WebsiteBackgroundExporter에서 제외된 씬 필터링
- BackgroundSceneLoaderWindow UI 개선:
  - 컨텍스트 메뉴에 '웹사이트 업로드 제외' 토글 추가
  - 그리드 뷰: 제외된 씬에 빨간 X 표시
  - 리스트 뷰: 제외된 씬에 [제외] 텍스트 표시

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Assets/Scripts/Streamingle/StreamingleControl/Background/BackgroundSceneData.cs

@@ -15,6 +15,7 @@ namespace Streamingle.Background
         public string categoryName;        // 카테고리 (폴더명, 예: [공용]농구장)
         public string thumbnailPath;       // 썸네일 이미지 경로
         public Texture2D thumbnail;        // 로드된 썸네일 (런타임용)
+        public bool excludeFromWeb;        // 웹사이트 업로드 제외 여부
 
         public string DisplayName => sceneName;
         public string Category => ExtractCategory(categoryName);

Assets/Scripts/Streamingle/StreamingleControl/Background/Editor/BackgroundSceneLoaderWindow.cs

@@ -934,6 +934,14 @@ namespace Streamingle.Background.Editor
                 GUI.Label(thumbnailRect, "No\nThumbnail", new GUIStyle(EditorStyles.centeredGreyMiniLabel) { wordWrap = true, alignment = TextAnchor.MiddleCenter });
             }
 
+            // 웹 제외 표시
+            if (sceneInfo.excludeFromWeb)
+            {
+                var excludeRect = new Rect(rect.x + THUMBNAIL_SIZE - 22, rect.y + 4, 18, 18);
+                EditorGUI.DrawRect(excludeRect, new Color(0.8f, 0.2f, 0.2f, 0.9f));
+                GUI.Label(excludeRect, "X", new GUIStyle(EditorStyles.boldLabel) { alignment = TextAnchor.MiddleCenter, normal = { textColor = Color.white } });
+            }
+
             // 씬 이름
             var labelRect = new Rect(rect.x, rect.y + THUMBNAIL_SIZE, THUMBNAIL_SIZE, 25);
             GUI.Label(labelRect, sceneInfo.sceneName, new GUIStyle(EditorStyles.miniLabel) { alignment = TextAnchor.MiddleCenter, wordWrap = true, clipping = TextClipping.Clip });
@@ -1002,8 +1010,14 @@ namespace Streamingle.Background.Editor
             // 씬 정보
             EditorGUILayout.BeginVertical();
 
+            EditorGUILayout.BeginHorizontal();
             var style = isCurrentScene ? EditorStyles.boldLabel : EditorStyles.label;
             EditorGUILayout.LabelField(sceneInfo.sceneName, style);
+            if (sceneInfo.excludeFromWeb)
+            {
+                GUILayout.Label("[제외]", new GUIStyle(EditorStyles.miniLabel) { normal = { textColor = new Color(0.9f, 0.3f, 0.3f) } }, GUILayout.Width(35));
+            }
+            EditorGUILayout.EndHorizontal();
             EditorGUILayout.LabelField(sceneInfo.categoryName, EditorStyles.miniLabel);
 
             EditorGUILayout.EndVertical();
@@ -1040,10 +1054,23 @@ namespace Streamingle.Background.Editor
             menu.AddItem(new GUIContent("폴더 열기"), false, () => RevealInFinder(sceneInfo));
             menu.AddSeparator("");
             menu.AddItem(new GUIContent("썸네일 생성"), false, () => CreateThumbnail(sceneInfo));
+            menu.AddSeparator("");
+            menu.AddItem(new GUIContent("웹사이트 업로드 제외"), sceneInfo.excludeFromWeb, () => ToggleExcludeFromWeb(sceneInfo));
 
             menu.ShowAsContext();
         }
 
+        private void ToggleExcludeFromWeb(BackgroundSceneInfo sceneInfo)
+        {
+            sceneInfo.excludeFromWeb = !sceneInfo.excludeFromWeb;
+            EditorUtility.SetDirty(_database);
+            AssetDatabase.SaveAssets();
+
+            string status = sceneInfo.excludeFromWeb ? "제외됨" : "포함됨";
+            UnityEngine.Debug.Log($"[BackgroundSceneLoader] '{sceneInfo.sceneName}' 웹 업로드 {status}");
+            Repaint();
+        }
+
         private void LoadScene(BackgroundSceneInfo sceneInfo, LoadSceneMode mode = LoadSceneMode.Additive)
         {
             if (_isLoading)

Assets/Scripts/Streamingle/StreamingleControl/Background/Editor/BackgroundThumbnailCapture.cs

@@ -1,3 +1,4 @@
+using System;
 using System.IO;
 using UnityEditor;
 using UnityEngine;

Assets/Scripts/Streamingle/StreamingleControl/Background/Editor/WebsiteBackgroundExporter.cs

@@ -191,6 +191,10 @@ namespace Streamingle.Background.Editor
 
                 foreach (var sceneInfo in _database.scenes)
                 {
+                    // 웹 업로드 제외된 씬은 스킵
+                    if (sceneInfo.excludeFromWeb)
+                        continue;
+
                     var item = new WebsiteBackgroundItem
                     {
                         sceneName = sceneInfo.sceneName,