AX Agent 실행 준비 로직을 엔진으로 추가 이관

- AxAgentExecutionEngine에 PreparedExecution, PrepareExecution, NormalizeAssistantContent를 추가해 실행 준비와 최종 응답 보정 책임을 더 모음

- ChatWindow의 일반 전송과 재생성이 PrepareExecutionForConversation을 통해 같은 준비 경로를 쓰도록 정리함

- Cowork/Code 시스템 프롬프트 선택, 실행 모드 판정, 프롬프트 스택 조합, outbound message 준비의 중복 분기를 줄임

- 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/Services/Agent/AxAgentExecutionEngine.cs

@@ -12,6 +12,10 @@ public sealed class AxAgentExecutionEngine
 {
     public sealed record PreparedTurn(List<ChatMessage> Messages);
     public sealed record ExecutionMode(bool UseAgentLoop, bool UseStreamingTransport, string? TaskSystemPrompt);
+    public sealed record PreparedExecution(
+        ExecutionMode Mode,
+        IReadOnlyList<string> PromptStack,
+        List<ChatMessage> Messages);
 
     public IReadOnlyList<string> BuildPromptStack(
         string? conversationSystem,
@@ -44,6 +48,32 @@ public sealed class AxAgentExecutionEngine
         return new ExecutionMode(false, false, null);
     }
 
+    public PreparedExecution PrepareExecution(
+        ChatConversation conversation,
+        string runTab,
+        bool streamingEnabled,
+        string resolvedService,
+        string? conversationSystem,
+        string? slashSystem,
+        string? coworkSystemPrompt,
+        string? codeSystemPrompt,
+        string? fileContext = null,
+        IReadOnlyList<ImageAttachment>? images = null)
+    {
+        var mode = ResolveExecutionMode(
+            runTab,
+            streamingEnabled,
+            resolvedService,
+            coworkSystemPrompt,
+            codeSystemPrompt);
+        var promptStack = BuildPromptStack(
+            conversationSystem,
+            slashSystem,
+            mode.TaskSystemPrompt);
+        var preparedTurn = PrepareTurn(conversation, promptStack, fileContext, images);
+        return new PreparedExecution(mode, promptStack, preparedTurn.Messages);
+    }
+
     public PreparedTurn PrepareTurn(
         ChatConversation conversation,
         IEnumerable<string?> systemPrompts,
@@ -103,6 +133,33 @@ public sealed class AxAgentExecutionEngine
         return assistant;
     }
 
+    public string NormalizeAssistantContent(
+        ChatConversation conversation,
+        string runTab,
+        string? content)
+    {
+        if (!string.IsNullOrWhiteSpace(content))
+            return content;
+
+        var latestEventSummary = conversation.ExecutionEvents?
+            .Where(evt => !string.IsNullOrWhiteSpace(evt.Summary))
+            .OrderByDescending(evt => evt.Timestamp)
+            .Select(evt => evt.Summary.Trim())
+            .FirstOrDefault();
+
+        if (!string.IsNullOrWhiteSpace(latestEventSummary))
+        {
+            return runTab switch
+            {
+                "Cowork" => $"코워크 작업이 완료되었습니다.\n\n{latestEventSummary}",
+                "Code" => $"코드 작업이 완료되었습니다.\n\n{latestEventSummary}",
+                _ => latestEventSummary,
+            };
+        }
+
+        return "(빈 응답)";
+    }
+
     private static ChatMessage CloneMessage(ChatMessage source)
     {
         return new ChatMessage

src/AxCopilot/Views/ChatWindow.xaml.cs

@@ -5728,30 +5728,6 @@ public partial class ChatWindow : Window
             : ScrollBarVisibility.Disabled;
     }
 
-    private static string BuildAssistantFallbackContent(ChatConversation conv, string runTab, string? content)
-    {
-        if (!string.IsNullOrWhiteSpace(content))
-            return content;
-
-        var latestEventSummary = conv.ExecutionEvents?
-            .Where(evt => !string.IsNullOrWhiteSpace(evt.Summary))
-            .OrderByDescending(evt => evt.Timestamp)
-            .Select(evt => evt.Summary.Trim())
-            .FirstOrDefault();
-
-        if (!string.IsNullOrWhiteSpace(latestEventSummary))
-        {
-            return runTab switch
-            {
-                "Cowork" => $"코워크 작업이 완료되었습니다.\n\n{latestEventSummary}",
-                "Code" => $"코드 작업이 완료되었습니다.\n\n{latestEventSummary}",
-                _ => latestEventSummary,
-            };
-        }
-
-        return "(빈 응답)";
-    }
-
     private static void SyncLatestAssistantMessage(ChatConversation conv, string content)
     {
         if (conv.Messages.Count == 0)
@@ -8393,27 +8369,14 @@ public partial class ChatWindow : Window
                 if (_attachedFiles.Count == 0) AttachedFilesPanel.Visibility = Visibility.Collapsed;
             }
 
-            var coworkSystem = string.Equals(runTab, "Cowork", StringComparison.OrdinalIgnoreCase)
-                ? BuildCoworkSystemPrompt()
-                : null;
-            var codeSystem = string.Equals(runTab, "Code", StringComparison.OrdinalIgnoreCase)
-                ? BuildCodeSystemPrompt()
-                : null;
-            var (resolvedService, _) = _llm.GetCurrentModelInfo();
-            var executionMode = _chatEngine.ResolveExecutionMode(
+            var preparedExecution = PrepareExecutionForConversation(
+                conv,
                 runTab,
-                _settings.Settings.Llm.Streaming,
-                resolvedService,
-                coworkSystem,
-                codeSystem);
-            var promptStack = _chatEngine.BuildPromptStack(
-                conv.SystemCommand,
                 slashSystem,
-                executionMode.TaskSystemPrompt);
-
-            sendMessages = _chatEngine
-                .PrepareTurn(conv, promptStack, fileContext, outboundImages)
-                .Messages;
+                fileContext,
+                outboundImages);
+            var executionMode = preparedExecution.Mode;
+            sendMessages = preparedExecution.Messages;
 
             // ── 전송 전 컨텍스트 사전 압축 ──
             {
@@ -8502,7 +8465,7 @@ public partial class ChatWindow : Window
             SetStatusIdle();
         }
 
-        assistantContent = BuildAssistantFallbackContent(conv, runTab, assistantContent);
+        assistantContent = _chatEngine.NormalizeAssistantContent(conv, runTab, assistantContent);
         if (runTab is "Cowork" or "Code")
             conv.ShowExecutionHistory = false;
 
@@ -8596,6 +8559,34 @@ public partial class ChatWindow : Window
         }
     }
 
+    private AxAgentExecutionEngine.PreparedExecution PrepareExecutionForConversation(
+        ChatConversation conversation,
+        string runTab,
+        string? slashSystem,
+        string? fileContext = null,
+        IReadOnlyList<ImageAttachment>? images = null)
+    {
+        var coworkSystem = string.Equals(runTab, "Cowork", StringComparison.OrdinalIgnoreCase)
+            ? BuildCoworkSystemPrompt()
+            : null;
+        var codeSystem = string.Equals(runTab, "Code", StringComparison.OrdinalIgnoreCase)
+            ? BuildCodeSystemPrompt()
+            : null;
+        var (resolvedService, _) = _llm.GetCurrentModelInfo();
+
+        return _chatEngine.PrepareExecution(
+            conversation,
+            runTab,
+            _settings.Settings.Llm.Streaming,
+            resolvedService,
+            conversation.SystemCommand,
+            slashSystem,
+            coworkSystem,
+            codeSystem,
+            fileContext,
+            images);
+    }
+
     // ─── 코워크 에이전트 지원 ────────────────────────────────────────────
 
     private string BuildCoworkSystemPrompt()
@@ -10987,27 +10978,12 @@ public partial class ChatWindow : Window
 
         try
         {
-            var coworkSystem = string.Equals(runTab, "Cowork", StringComparison.OrdinalIgnoreCase)
-                ? BuildCoworkSystemPrompt()
-                : null;
-            var codeSystem = string.Equals(runTab, "Code", StringComparison.OrdinalIgnoreCase)
-                ? BuildCodeSystemPrompt()
-                : null;
-            var (resolvedService, _) = _llm.GetCurrentModelInfo();
-            var executionMode = _chatEngine.ResolveExecutionMode(
-                runTab,
-                _settings.Settings.Llm.Streaming,
-                resolvedService,
-                coworkSystem,
-                codeSystem);
-            var promptStack = _chatEngine.BuildPromptStack(
-                conv.SystemCommand,
-                null,
-                executionMode.TaskSystemPrompt);
-
             List<ChatMessage> sendMessages;
+            AxAgentExecutionEngine.PreparedExecution preparedExecution;
             lock (_convLock)
-                sendMessages = _chatEngine.PrepareTurn(conv, promptStack, null, null).Messages;
+                preparedExecution = PrepareExecutionForConversation(conv, runTab, null);
+            var executionMode = preparedExecution.Mode;
+            sendMessages = preparedExecution.Messages;
 
             var response = executionMode.UseAgentLoop
                 ? await RunAgentLoopAsync(runTab, runTab, conv, sendMessages, _streamCts.Token)
@@ -11046,7 +11022,7 @@ public partial class ChatWindow : Window
             SetStatusIdle();
         }
 
-        assistantContent = BuildAssistantFallbackContent(conv, runTab, assistantContent);
+        assistantContent = _chatEngine.NormalizeAssistantContent(conv, runTab, assistantContent);
         if (runTab is "Cowork" or "Code")
             conv.ShowExecutionHistory = false;
         lock (_convLock)