체크포인트 로그에 레벨 소요시간 표시

Program.cs

@@ -194,7 +194,7 @@ internal static class Program
         checkpointPath = string.IsNullOrWhiteSpace(checkpointPath) ? "stage_checkpoint.json" : checkpointPath;
         var checkpointEnabled = !string.IsNullOrWhiteSpace(checkpointPath);
 
-        void SaveCheckpoint(List<GeneratedLevel> snapshot, int lastId)
+        void SaveCheckpoint(List<GeneratedLevel> snapshot, int lastId, TimeSpan levelElapsed)
         {
             if (!checkpointEnabled) return;
             // 매 레벨마다(또는 마지막 레벨) 누적 JSON을 디스크에 기록한다.
@@ -202,7 +202,7 @@ internal static class Program
             {
                 var json = JsonSerializer.Serialize(snapshot, options);
                 File.WriteAllText(checkpointPath, json);
-                status.ShowLine($"체크포인트 저장: 레벨 {lastId}까지 -> {checkpointPath}");
+                status.ShowLine($"체크포인트 저장: 레벨 {lastId}까지 ({StatusReporter.FormatDuration(levelElapsed)}) -> {checkpointPath}");
             }
             catch (Exception ex)
             {
@@ -488,7 +488,7 @@ internal sealed class LevelGenerator
         _trace = Environment.GetEnvironmentVariable("NEKOBAN_DEBUG") == "1";
     }
 
-    public List<GeneratedLevel> BuildRange(int startId, int endId, Action<List<GeneratedLevel>, int>? onCheckpoint = null)
+    public List<GeneratedLevel> BuildRange(int startId, int endId, Action<List<GeneratedLevel>, int, TimeSpan>? onCheckpoint = null)
     {
         foreach (var band in _bands)
         {
@@ -506,8 +506,9 @@ internal sealed class LevelGenerator
             var levelStopwatch = Stopwatch.StartNew();
             var level = BuildSingle(id, band, levelStopwatch);
             level = TrimLevel(level);
+            levelStopwatch.Stop();
             output.Add(level);
-            onCheckpoint?.Invoke(output, id);
+            onCheckpoint?.Invoke(output, id, levelStopwatch.Elapsed);
         }
 
         return output;