feat: 리밸런싱 엔진 V1 + GAS 버그 수정 (2026-06-13)

주요 변경:
- tools/build_rebalance_engine_v1.py: REBALANCE_ENGINE_V1 신규
  * account_snapshot 직접 합산(_build_snap_position_map) → 소수주 분리 행 병합
  * 레짐 소스 macro.REGIME_PRELIM 최우선 (GAS 와 동일)
- src/gas_adapter_parts/gdf_06_rebalance.gs: runRebalanceSheet_() 신규
  * Logger.log / getSpreadsheet_() 로 run_all 연동 수정
- src/gas_adapter_parts/gdc_01_fetch_fundamentals.gs
  * _mergePositionRecord_(): 소수주 중복 행 합산 신규
  * parseInt → parseFloat (qty, availQty)
- src/gas_adapter_parts/gdf_01_price_metrics.gs
  * 미보유 종목 SELL_READY → WATCH_EXIT_SIGNAL
- spec/41_release_dag.yaml: build_rebalance_sheet 노드 추가 (step_count 63)
- spec/51_formula_lifecycle_registry.yaml: REBALANCE_ENGINE_V1 등록

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

tools/run_oneoff_eod_backfill.ps1

@@ -0,0 +1,7 @@
+$ErrorActionPreference = "Stop"
+
+python .\tools\backfill_eod_replay_history.py --json .\GatherTradingData.json --history .\Temp\proposal_evaluation_history.json --lookback_days 110 --max_trade_days 55
+python .\tools\build_evaluation_history_coverage_v1.py --history .\Temp\proposal_evaluation_history.json --out .\Temp\evaluation_history_coverage_v1.json
+python .\tools\build_outcome_quality_score_v1.py --json .\GatherTradingData.json --out .\Temp\outcome_quality_score_v1.json --policy .\spec\strategy_execution_lock_policy.yaml
+
+Write-Host "ONEOFF_BACKFILL_DONE"