claude-code 기준 provider 호환성과 compact 후속 흐름을 보강한다

- OpenAI 호환 tool_choice 400 오류에 대한 일반 fallback을 추가하고 Qwen·LLaMA·DeepSeek 계열 vLLM의 도구 호출 프로파일을 더 보수적으로 조정

- compact 이후 branch context와 최근 tool state를 query view에 재주입하고 UI 표현 수준에 맞춰 compact 카드/컨텍스트 사용 팝업/최종 보고 밀도를 세분화

- README와 DEVELOPMENT 문서 이력을 2026-04-12 23:45 KST 기준으로 갱신

- 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/AgentQueryContextBuilder.cs

@@ -157,21 +157,39 @@ public static class AgentQueryContextBuilder
             string.Equals(m.MetaKind, "microcompact_boundary", StringComparison.OrdinalIgnoreCase)
             || string.Equals(m.MetaKind, "session_memory_compaction", StringComparison.OrdinalIgnoreCase)
             || string.Equals(m.MetaKind, "collapsed_boundary", StringComparison.OrdinalIgnoreCase));
+        var branchContextCount = messages.Count(m =>
+            string.Equals(m.MetaKind, "branch_context", StringComparison.OrdinalIgnoreCase));
         var structuredToolHistoryCount = messages.Count(m =>
         {
             var content = m.Content ?? "";
             return content.StartsWith("{\"_tool_use_blocks\"", StringComparison.Ordinal)
                    || content.StartsWith("{\"type\":\"tool_result\"", StringComparison.Ordinal);
         });
+        var recentToolNames = messages
+            .Where(m => m.Role == "user")
+            .Select(m => TryExtractToolResultToolName(m, out var toolName) ? toolName : "")
+            .Where(toolName => !string.IsNullOrWhiteSpace(toolName))
+            .Distinct(StringComparer.OrdinalIgnoreCase)
+            .Take(4)
+            .ToList();
 
-        if (attachedFiles.Count == 0 && imageCount == 0 && compactSummaryCount == 0 && structuredToolHistoryCount == 0)
+        if (attachedFiles.Count == 0
+            && imageCount == 0
+            && compactSummaryCount == 0
+            && structuredToolHistoryCount == 0
+            && branchContextCount == 0
+            && recentToolNames.Count == 0)
             return;
 
         var lines = new List<string> { "[post-compact context]" };
         if (compactSummaryCount > 0)
             lines.Add($"restored compact summaries: {compactSummaryCount}");
+        if (branchContextCount > 0)
+            lines.Add($"restored branch context: {branchContextCount}");
         if (structuredToolHistoryCount > 0)
             lines.Add($"restored tool history blocks: {structuredToolHistoryCount}");
+        if (recentToolNames.Count > 0)
+            lines.Add("restored recent tools: " + string.Join(", ", recentToolNames));
         if (attachedFiles.Count > 0)
             lines.Add("restored file refs: " + string.Join(", ", attachedFiles));
         if (imageCount > 0)
@@ -190,4 +208,28 @@ public static class AgentQueryContextBuilder
             AttachedFiles = attachedFiles.Count > 0 ? attachedFiles : null,
         });
     }
+
+    private static bool TryExtractToolResultToolName(ChatMessage message, out string toolName)
+    {
+        toolName = "";
+        if (!string.Equals(message.Role, "user", StringComparison.OrdinalIgnoreCase)
+            || string.IsNullOrWhiteSpace(message.Content)
+            || !message.Content.StartsWith("{\"type\":\"tool_result\"", StringComparison.Ordinal))
+            return false;
+
+        try
+        {
+            using var doc = System.Text.Json.JsonDocument.Parse(message.Content);
+            if (doc.RootElement.TryGetProperty("tool_name", out var toolNameEl))
+            {
+                toolName = toolNameEl.GetString() ?? "";
+                return !string.IsNullOrWhiteSpace(toolName);
+            }
+        }
+        catch
+        {
+        }
+
+        return false;
+    }
 }