fix: CI venv hash-cache + sector exposure renderer + auditor registration

- ci.yml: venv 해시 기반 캐싱 적용 (validate_specs.py md5 기준), requirements.txt 불필요 스텝 제거
- harness_coverage_auditor.py: sector_trend_analysis.py, etf_representative_monitor.py PY_FILES 등록
- render_operational_report.py: _portfolio_sector_exposure_summary 개선 — account_snapshot 실데이터 집계 + Top5 섹터별 상위 보유 종목 상세 테이블 + _display() 누락값 표시
- update_workbook_sector_insights.py: row-2 헤더 처리 + sector_holdings 상세 추적 + _display() 누락값 표시
- operational_report_contract.py: portfolio_sector_exposure_summary REPORT_SECTION_ORDER 등록
- validate_report_section_completeness_v1.py: 동일 섹션 추가
- build_architecture_boundaries_v2.py: sparkline/idx/basket-delta UI 프리미티브 whitelist 추가
- runtime/refactor_baseline_v1.yaml: 엔트로피 베이스라인 갱신 (1692 files, gate=PASS)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tools/validate_report_section_completeness_v1.py

@@ -19,6 +19,7 @@ REPORT_SECTION_ORDER = [
     "concise_hts_input_sheet", "watch_breakout_gate",
     "single_conclusion", "immediate_execution_playbook", "market_context_learning_note",
     "portfolio_performance_summary",
+    "portfolio_sector_exposure_summary",
     "sector_trend_analysis_v1",
     "etf_representative_monitor_v1",
     "investment_quality_headline", "operational_truth_score",