Code 탭 컨텍스트 누적 신뢰성과 작업 연속성을 전면 보강한다

이번 커밋은 Code 탭 장기 실행에서 build/file 근거가 너무 빨리 축약되고, 이전 수정 맥락이 다음 LLM 요청에 안정적으로 누적되지 않던 문제를 해결하기 위한 전면 보강을 담는다.

핵심 수정사항:
- CodeTaskWorkingSetService를 추가해 최근 생성 디렉터리, 최근 읽기/쓰기 파일, 최신 build/test 진단, 다음 복구 초점을 구조화된 working set으로 유지하고 각 반복 요청에 보조 system context로 주입한다.
- AgentQueryContextBuilder와 AgentToolResultBudget에 code profile을 도입해 protected recent window와 tool_result budget을 확장하고 build_run, test_loop, file_read, multi_read, lsp_code_intel, git_tool 같은 고가치 evidence가 기본 탭보다 덜 잘리도록 조정한다.
- AgentLoopIterationPreparationService와 AgentLoopLlmRequestPreparationService를 확장해 query-context options와 supplemental messages를 함께 전달하고, AgentLoopService에서는 Code 탭에서 generic session learnings 대신 working set 중심으로 요청을 구성하도록 변경한다.
- ChatWindow.UtilityPresentation에서 workspace context 첫 부트스트랩을 강화해 .ax-context.md가 아직 없더라도 첫 요청 시점부터 background generation과 language workflow bootstrap hints가 반영되도록 수정한다.
- LlmService.ToolUse에서 historical tool trace sanitization 결과를 assistant flatten/orphan conversion 건수로 요약 로그에 남겨 tool-trace 불변식 문제를 추적 가능하게 만든다.
- 관련 테스트를 추가·갱신해 working set 누적, code profile budget, supplemental message 주입, query-context option 전달을 회귀 고정한다.

검증 결과:
- dotnet build src/AxCopilot/AxCopilot.csproj -c Release -v minimal -p:OutputPath=bin\\verify_context_reliability_full\\ -p:IntermediateOutputPath=obj\\verify_context_reliability_full\\ : 경고 0 / 오류 0
- dotnet test src/AxCopilot.Tests/AxCopilot.Tests.csproj -c Release -v minimal --filter "AgentQueryContextBuilderTests|AgentToolResultBudgetTests|AgentLoopIterationPreparationServiceTests|AgentLoopLlmRequestPreparationServiceTests|CodeTaskWorkingSetServiceTests|AgentLoopCodeQualityTests" -p:OutputPath=bin\\verify_context_reliability_full_tests\\ -p:IntermediateOutputPath=obj\\verify_context_reliability_full_tests\\ : 통과 150
- dotnet test src/AxCopilot.Tests/AxCopilot.Tests.csproj -c Release -v minimal --filter "AgentLoopE2ETests|AgentMessageInvariantHelperTests" -p:OutputPath=bin\\verify_context_reliability_e2e\\ -p:IntermediateOutputPath=obj\\verify_context_reliability_e2e\\ : 통과 21

docs/CODE_CONTEXT_RELIABILITY_PLAN.md

@@ -247,3 +247,28 @@ AX already has similar mechanisms, but the Code flow still lacks stronger workin
 - better structural consistency for project generation and large edits
 - less drift in long-running Code tasks
 - fewer quality losses caused by broken strings and low-signal context replacements
+
+## Latest Delivery
+
+Updated: 2026-04-16 01:41 (KST)
+
+- Delivered in this pass:
+  - Phase 1 foundation:
+    - `ChatWindow.UtilityPresentation.cs` now bootstraps workspace context generation on first access and returns language-workflow fallback hints while `.ax-context.md` is still being generated.
+    - `AgentLoopService.cs` now records `query_context` workflow transitions with query-window, budget, supplemental-context, and working-set summaries.
+  - Phase 2 foundation:
+    - `CodeTaskWorkingSetService.cs` adds a Code-only structured ledger for:
+      - goal
+      - selected scaffold/profile
+      - created directories
+      - recent reads/writes
+      - latest diagnostics
+      - next repair focus
+    - the working set is injected into each Code request as a supplemental `code_working_set` system message.
+  - Phase 3 foundation:
+    - `AgentToolResultBudget.cs` and `AgentQueryContextBuilder.cs` now expose a `code` query profile with a larger protected-recent window and larger retained budgets for `build_run`, `test_loop`, `process`, `file_read`, `multi_read`, `lsp_code_intel`, and `git_tool`.
+  - Phase 4 observability step:
+    - `LlmService.ToolUse.cs` now logs sanitization counts for flattened assistant tool traces and converted orphan tool messages, so tool-trace repair frequency can be measured per run.
+- Remaining follow-up:
+  - extend pre-request tool-trace validation so the flattening/orphan repair count trends toward zero rather than being logged after repair
+  - replace more mojibake prompt/status strings in active Code execution paths with English equivalents