post-compaction 추적과 대화별 사용량 계측 보강

- claude-code의 post-compaction 플래그 흐름을 참고해 compact 직후 첫 응답을 별도로 추적하고 대화 단위 후속 사용량을 집계함

- ChatConversation에 pending post-compaction, 응답 회수, prompt/completion token 누적 필드를 추가하고 AX Agent 컨텍스트 카드 hover에 표시함

- README 및 docs/DEVELOPMENT.md에 2026-04-04 23:47 (KST) 기준 이력을 반영함

- 검증: dotnet build src/AxCopilot/AxCopilot.csproj -c Release -v minimal -p:OutputPath=bin\\verify\\ -p:IntermediateOutputPath=obj\\verify\\ (경고 0 / 오류 0)

src/AxCopilot/Models/ChatModels.cs

@@ -175,6 +175,18 @@ public class ChatConversation
 
     [JsonPropertyName("lastCompactionStageSummary")]
     public string? LastCompactionStageSummary { get; set; }
+
+    [JsonPropertyName("pendingPostCompaction")]
+    public bool PendingPostCompaction { get; set; }
+
+    [JsonPropertyName("postCompactionResponseCount")]
+    public int PostCompactionResponseCount { get; set; }
+
+    [JsonPropertyName("postCompactionPromptTokens")]
+    public int PostCompactionPromptTokens { get; set; }
+
+    [JsonPropertyName("postCompactionCompletionTokens")]
+    public int PostCompactionCompletionTokens { get; set; }
 }
 
 public class ChatAgentRunRecord

src/AxCopilot/Views/ChatWindow.xaml.cs

@@ -107,6 +107,10 @@ public partial class ChatWindow : Window
     private int _sessionMemoryCompactionCount;
     private int _sessionMicrocompactBoundaryCount;
     private int _sessionSnipCompactionCount;
+    private bool _pendingPostCompaction;
+    private int _sessionPostCompactionResponseCount;
+    private int _sessionPostCompactionPromptTokens;
+    private int _sessionPostCompactionCompletionTokens;
     private void ApplyQuickActionVisual(Button button, bool active, string activeBg, string activeFg)
     {
         if (button?.Content is not string text)
@@ -1732,6 +1736,10 @@ public partial class ChatWindow : Window
         _sessionMemoryCompactionCount = conv?.SessionMemoryCompactionCount ?? 0;
         _sessionMicrocompactBoundaryCount = conv?.MicrocompactBoundaryCount ?? 0;
         _sessionSnipCompactionCount = conv?.SnipCompactionCount ?? 0;
+        _pendingPostCompaction = conv?.PendingPostCompaction ?? false;
+        _sessionPostCompactionResponseCount = conv?.PostCompactionResponseCount ?? 0;
+        _sessionPostCompactionPromptTokens = conv?.PostCompactionPromptTokens ?? 0;
+        _sessionPostCompactionCompletionTokens = conv?.PostCompactionCompletionTokens ?? 0;
         _lastCompactionAt = conv?.LastCompactionAt;
         _lastCompactionWasAutomatic = conv?.LastCompactionWasAutomatic ?? false;
         _lastCompactionBeforeTokens = conv?.LastCompactionBeforeTokens;
@@ -10939,10 +10947,12 @@ public partial class ChatWindow : Window
             ? _agentCumulativeOutputTokens
             : usage?.CompletionTokens ?? 0;
 
+        var wasPostCompactionResponse = _pendingPostCompaction;
         if (displayInput > 0 || displayOutput > 0)
         {
             UpdateStatusTokens(displayInput, displayOutput);
             Services.UsageStatisticsService.RecordTokens(displayInput, displayOutput);
+            ConsumePostCompactionUsageIfNeeded(displayInput, displayOutput);
         }
         string tokenText;
         if (displayInput > 0 || displayOutput > 0)
@@ -10952,9 +10962,10 @@ public partial class ChatWindow : Window
         else
             tokenText = $"~{FormatTokenCount(EstimateTokenCount(finalContent))} tokens";
 
+        var postCompactSuffix = wasPostCompactionResponse ? "  ·  compact 직후" : "";
         var metaText = new TextBlock
         {
-            Text = $"{elapsedText}  ·  {tokenText}",
+            Text = $"{elapsedText}  ·  {tokenText}{postCompactSuffix}",
             FontSize = 9.5,
             Foreground = TryFindResource("SecondaryText") as Brush ?? Brushes.Gray,
             HorizontalAlignment = HorizontalAlignment.Right,
@@ -16532,6 +16543,11 @@ private static (string icon, string label, string bgHex, string fgHex) GetDecisi
               $"세션 절감: {Services.TokenEstimator.Format(_sessionCompactionSavedTokens)} tokens\n" +
               $"세션 메모리 {_sessionMemoryCompactionCount:N0}회 · 경계 {_sessionMicrocompactBoundaryCount:N0}건 · snip {_sessionSnipCompactionCount:N0}건"
             : "";
+        var postCompactionUsage = _sessionPostCompactionResponseCount > 0
+            ? $"\ncompact 이후 응답: {_sessionPostCompactionResponseCount:N0}회\n" +
+              $"compact 이후 사용량: {Services.TokenEstimator.Format(_sessionPostCompactionPromptTokens)} + {Services.TokenEstimator.Format(_sessionPostCompactionCompletionTokens)} = {Services.TokenEstimator.Format(_sessionPostCompactionPromptTokens + _sessionPostCompactionCompletionTokens)} tokens"
+            : "";
+        var pendingPostCompaction = _pendingPostCompaction ? "\ncompact 후 첫 응답 대기 중" : "";
 
         TokenUsageCard.ToolTip =
             $"상태: {summary}\n" +
@@ -16540,7 +16556,9 @@ private static (string icon, string label, string bgHex, string fgHex) GetDecisi
             $"자동 압축 시작: {triggerPercent}%\n" +
             $"현재 입력 초안 포함" +
             compactHistory +
-            compactSession;
+            compactSession +
+            postCompactionUsage +
+            pendingPostCompaction;
 
         UpdateCircularUsageArc(TokenUsageArc, usageRatio, 18, 18, 14);
         PositionThresholdMarker(TokenUsageThresholdMarker, triggerRatio, 18, 18, 14, 3);
@@ -16605,6 +16623,7 @@ private static (string icon, string label, string bgHex, string fgHex) GetDecisi
         _sessionMemoryCompactionCount += result.SessionMemoryApplied ? 1 : 0;
         _sessionMicrocompactBoundaryCount += result.MicrocompactBoundaryCount;
         _sessionSnipCompactionCount += result.SnippedMessageCount + result.CollapsedBoundaryCount;
+        _pendingPostCompaction = true;
         if (wasAutomatic)
             _sessionAutomaticCompactionCount++;
         else
@@ -16627,6 +16646,29 @@ private static (string icon, string label, string bgHex, string fgHex) GetDecisi
         conv.LastCompactionBeforeTokens = beforeTokens;
         conv.LastCompactionAfterTokens = afterTokens;
         conv.LastCompactionStageSummary = _lastCompactionStageSummary;
+        conv.PendingPostCompaction = true;
+        try { _storage.Save(conv); } catch { }
+    }
+
+    private void ConsumePostCompactionUsageIfNeeded(int promptTokens, int completionTokens)
+    {
+        if (!_pendingPostCompaction)
+            return;
+
+        _pendingPostCompaction = false;
+        _sessionPostCompactionResponseCount++;
+        _sessionPostCompactionPromptTokens += Math.Max(0, promptTokens);
+        _sessionPostCompactionCompletionTokens += Math.Max(0, completionTokens);
+
+        ChatConversation? conv;
+        lock (_convLock) conv = _currentConversation;
+        if (conv == null)
+            return;
+
+        conv.PendingPostCompaction = false;
+        conv.PostCompactionResponseCount = _sessionPostCompactionResponseCount;
+        conv.PostCompactionPromptTokens = _sessionPostCompactionPromptTokens;
+        conv.PostCompactionCompletionTokens = _sessionPostCompactionCompletionTokens;
         try { _storage.Save(conv); } catch { }
     }