feat: sector trend analysis + ETF representative monitor (DAG step_count 81->83)

- src/quant_engine/sector_trend_analysis.py: ETF proxy 기반 11개 섹터 동향 + smart money lens
- src/quant_engine/etf_representative_monitor.py: ETF 대표 종목 8개 추적 + 벤치마크 연동
- tools/build_sector_trend_analysis_v1.py: SECTOR_TREND_ANALYSIS_V1 Temp JSON 생성
- tools/build_etf_representative_monitor_v1.py: ETF_REPRESENTATIVE_MONITOR_V1 Temp JSON 생성
- tools/update_workbook_sector_insights.py: Google Sheets 섹터 인사이트 동기화
- spec/41_release_dag.yaml: step_count 81->83, wave_1에 2개 신규 노드 등록
- validate_engine_harness_gate.py: CHECK_87B (SECTOR_TREND_ANALYSIS_V1) + ETF monitor DAG 스텝 추가
- render_operational_report.py: sector_trend_analysis_v1 / etf_representative_monitor_v1 / portfolio_performance_summary 섹션 추가
- gas_lib.gs: doPost + syncSectorInsightSheets_ (섹터 인사이트 GAS 동기화 엔드포인트)

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

tools/validate_report_section_completeness_v1.py

@@ -18,6 +18,9 @@ REPORT_SECTION_ORDER = [
     "exec_safety_declaration", "final_judgment_table", "final_execution_decision",
     "concise_hts_input_sheet", "watch_breakout_gate",
     "single_conclusion", "immediate_execution_playbook", "market_context_learning_note",
+    "portfolio_performance_summary",
+    "sector_trend_analysis_v1",
+    "etf_representative_monitor_v1",
     "investment_quality_headline", "operational_truth_score",
     "execution_readiness_matrix", "pass_100_criteria",
     "today_decision_summary_card", "routing_serving_trace",