feat: Game scene — SongController bridges custom map to VRBeatsKit

- SongController: loads MP3 + Beat Saber JSON map, runs countdown (3→2→1→GO),
  spawns cubes via VR_BeatManager.Spawn() synced to audioSource.time
- NoteData → SpawnEventInfo mapping: position/lineLayer → x/y, colorType → ColorSide,
  cutDirection → Direction enum
- travelTimeOverride on SpawnEventInfo: each cube's travel time is back-calculated
  from remaining time at spawn moment, so simultaneous notes arrive at hit zone together
  regardless of frame-level spawn delay
- AudioManager: add PlayClip(AudioClip) and CurrentTime property
- VR_BeatManager: respect travelTimeOverride when non-zero
- Settings.asset: targetTravelTime 0.5 → 1.8 for natural Beat Saber approach feel
- SceneBuilder ④: auto-builds Game.unity from SaberStyle, wires SongController refs,
  registers in Build Settings
- LiberationSans SDF fallback updated with NanumGothic for Korean text support
- Remove unused SampleScene

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Assets/Editor/VRBeatSaberSceneBuilder.cs

@@ -3,11 +3,98 @@ using UnityEditor.SceneManagement;
 using UnityEngine;
 using UnityEngine.UI;
 using TMPro;
+using VRBeats;
+using VRBeats.ScriptableEvents;
 
 public static class VRBeatSaberSceneBuilder
 {
     private const string MenuScene = "Assets/VRBeatsKit/Scenes/Menu.unity";
 
+    // ─────────────────────────────────────────────
+    //  ④ Build Game Scene
+    //  SaberStyle 복제 → Game.unity 생성
+    //  PlayableManager 제거, SongController + 카운트다운 캔버스 추가
+    // ─────────────────────────────────────────────
+    [MenuItem("Tools/VRBeatSaber/④ Build Game Scene")]
+    public static void BuildGameScene()
+    {
+        const string saberStylePath = "Assets/VRBeatsKit/Scenes/SaberStyle.unity";
+        const string gamePath       = "Assets/Scenes/Game.unity";
+
+        // SaberStyle → Game.unity 복제 (이미 있으면 그냥 열기)
+        if (!AssetDatabase.LoadAssetAtPath<Object>(gamePath))
+        {
+            if (!AssetDatabase.CopyAsset(saberStylePath, gamePath))
+            {
+                Debug.LogError("[SceneBuilder] SaberStyle.unity 복제 실패");
+                return;
+            }
+            AssetDatabase.Refresh();
+        }
+
+        var scene = EditorSceneManager.OpenScene(gamePath, OpenSceneMode.Single);
+
+        // PlayableManager 제거 (PlayableDirector는 유지)
+        var pm = Object.FindObjectOfType<PlayableManager>();
+        if (pm != null)
+            Object.DestroyImmediate(pm);
+
+        // SongController GO 생성
+        var scGO           = new GameObject("SongController");
+        var songController = scGO.AddComponent<SongController>();
+
+        var cubePrefab      = AssetDatabase.LoadAssetAtPath<Spawneable>(
+            "Assets/VRBeatsKit/Prefabs/Spawneable/VR_BeatCube.prefab");
+        var onLevelComplete = AssetDatabase.LoadAssetAtPath<GameEvent>(
+            "Assets/VRBeatsKit/GameEvents/OnLevelComplete.asset");
+
+        // 카운트다운 캔버스 생성
+        var canvasGO = new GameObject("CountdownCanvas");
+        var canvas   = canvasGO.AddComponent<Canvas>();
+        canvas.renderMode   = RenderMode.ScreenSpaceOverlay;
+        canvas.sortingOrder = 100;
+        canvasGO.AddComponent<CanvasScaler>();
+        canvasGO.AddComponent<GraphicRaycaster>();
+
+        var countdownGO = new GameObject("CountdownText");
+        countdownGO.transform.SetParent(canvasGO.transform, false);
+        var cRect              = countdownGO.AddComponent<RectTransform>();
+        cRect.anchorMin        = new Vector2(0.5f, 0.5f);
+        cRect.anchorMax        = new Vector2(0.5f, 0.5f);
+        cRect.pivot            = new Vector2(0.5f, 0.5f);
+        cRect.anchoredPosition = Vector2.zero;
+        cRect.sizeDelta        = new Vector2(400f, 200f);
+        var cTmp               = countdownGO.AddComponent<TextMeshProUGUI>();
+        cTmp.text              = "";
+        cTmp.fontSize          = 120f;
+        cTmp.color             = Color.white;
+        cTmp.alignment         = TextAlignmentOptions.Center;
+        cTmp.fontStyle         = FontStyles.Bold;
+        countdownGO.SetActive(false);
+
+        // SongController 필드 연결
+        var scSO = new SerializedObject(songController);
+        scSO.FindProperty("cubePrefab")      .objectReferenceValue = cubePrefab;
+        scSO.FindProperty("onLevelComplete") .objectReferenceValue = onLevelComplete;
+        scSO.FindProperty("countdownText")   .objectReferenceValue = cTmp;
+        scSO.ApplyModifiedPropertiesWithoutUndo();
+
+        // Build Settings 에 Game.unity 추가
+        var scenes      = EditorBuildSettings.scenes;
+        bool exists     = System.Array.Exists(scenes, s => s.path == gamePath);
+        if (!exists)
+        {
+            var newList   = new EditorBuildSettingsScene[scenes.Length + 1];
+            System.Array.Copy(scenes, newList, scenes.Length);
+            newList[scenes.Length] = new EditorBuildSettingsScene(gamePath, true);
+            EditorBuildSettings.scenes = newList;
+        }
+
+        EditorSceneManager.MarkSceneDirty(scene);
+        EditorSceneManager.SaveScene(scene);
+        Debug.Log("[SceneBuilder] ✓ Game.unity 생성 완료");
+    }
+
     // ─────────────────────────────────────────────
     //  ③ Menu — Rebuild SongSelect Panel
     //