채팅 탭 SSE 스트리밍 응답 경로 복구 및 문서 반영

- Chat 탭 직접 대화 경로가 최종 응답만 한 번에 표시하던 문제를 수정하고 LlmService 스트리밍 경로를 실제 UI에 연결함\n- AxAgentExecutionEngine에서 비에이전트 채팅이 스트리밍 전송을 사용할 수 있도록 실행 모드를 조정함\n- ChatWindow에서 기존 스트리밍 컨테이너와 타이핑 타이머를 실제 전송 루프에 연결해 타자 치듯 점진적으로 응답이 보이게 함\n- README와 DEVELOPMENT 문서에 2026-04-07 02:23 (KST) 기준 변경 이력 반영\n- 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

@@ -49,7 +49,7 @@ public sealed class AxAgentExecutionEngine
         if (string.Equals(runTab, "Code", StringComparison.OrdinalIgnoreCase))
             return new ExecutionMode(true, false, codeSystemPrompt);
 
-        return new ExecutionMode(false, false, null);
+        return new ExecutionMode(false, streamingEnabled, null);
     }
 
     public PreparedExecution PrepareExecution(

src/AxCopilot/Views/ChatWindow.xaml.cs

@@ -5593,14 +5593,45 @@ public partial class ChatWindow : Window
         _elapsedTimer.Start();
         SetStatus(busyStatus, spinning: true);
 
+        StackPanel? streamingContainer = null;
+        TextBlock? streamingText = null;
+
         try
         {
-            var response = await _chatEngine.ExecutePreparedAsync(
-                preparedExecution,
-                (messages, token) => RunAgentLoopAsync(runTab, rememberTab, conversation, messages, token),
-                (messages, token) => _llm.SendAsync(messages.ToList(), token),
-                _streamCts.Token);
-            assistantContent = response;
+            if (!preparedExecution.Mode.UseAgentLoop && preparedExecution.Mode.UseStreamingTransport)
+            {
+                streamingContainer = CreateStreamingContainer(out var createdStreamText);
+                streamingText = createdStreamText;
+                _activeStreamText = streamingText;
+                _cachedStreamContent = "";
+                _displayedLength = 0;
+                _cursorVisible = true;
+                MessagePanel.Children.Add(streamingContainer);
+                ForceScrollToEnd();
+                _cursorTimer.Start();
+                _typingTimer.Start();
+
+                await foreach (var chunk in _llm.StreamAsync(preparedExecution.Messages.ToList(), _streamCts.Token))
+                {
+                    if (string.IsNullOrEmpty(chunk))
+                        continue;
+
+                    assistantContent += chunk;
+                    _cachedStreamContent = assistantContent;
+                    if (_activeStreamText != null && _displayedLength == 0)
+                        _activeStreamText.Text = _cursorVisible ? "\u258c" : " ";
+                }
+            }
+            else
+            {
+                var response = await _chatEngine.ExecutePreparedAsync(
+                    preparedExecution,
+                    (messages, token) => RunAgentLoopAsync(runTab, rememberTab, conversation, messages, token),
+                    (messages, token) => _llm.SendAsync(messages.ToList(), token),
+                    _streamCts.Token);
+                assistantContent = response;
+            }
+
             responseElapsedMs = Math.Max(0, (long)(DateTime.UtcNow - _streamStartTime).TotalMilliseconds);
             assistantMetaRunId = _appState.AgentRun.RunId;
             var usage = _llm.LastTokenUsage;
@@ -5618,8 +5649,11 @@ public partial class ChatWindow : Window
                 }
             }
             StopAiIconPulse();
-            _cachedStreamContent = response;
+            _cachedStreamContent = assistantContent;
             draftSucceeded = true;
+
+            if (streamingContainer != null && streamingText != null)
+                FinalizeStreamingContainer(streamingContainer, streamingText, assistantContent);
         }
         catch (OperationCanceledException)
         {
@@ -5627,6 +5661,8 @@ public partial class ChatWindow : Window
             assistantContent = finalized.Content;
             draftCancelled = finalized.Cancelled;
             draftFailure = finalized.FailureReason;
+            if (streamingContainer != null && streamingText != null)
+                FinalizeStreamingContainer(streamingContainer, streamingText, assistantContent);
         }
         catch (Exception ex)
         {
@@ -5634,6 +5670,8 @@ public partial class ChatWindow : Window
             assistantContent = finalized.Content;
             draftFailure = finalized.FailureReason;
             ShowToast("실패한 요청은 작업 요약에서 다시 시도할 수 있습니다.", "\uE783", 2600);
+            if (streamingContainer != null && streamingText != null)
+                FinalizeStreamingContainer(streamingContainer, streamingText, assistantContent);
         }
         finally
         {