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/validate_backdata_migration_state.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from collections import Counter
+from pathlib import Path
+
+from openpyxl import load_workbook
+
+
+ROOT = Path(__file__).resolve().parents[1]
+XLSX = ROOT / "GatherTradingData.xlsx"
+
+
+def main() -> int:
+    wb = load_workbook(XLSX, data_only=True)
+    if "backdata_feature_bank" not in wb.sheetnames:
+        print("FAIL: missing sheet backdata_feature_bank")
+        return 1
+    ws = wb["backdata_feature_bank"]
+    headers = [ws.cell(row=2, column=c).value for c in range(1, ws.max_column + 1)]
+    col = {str(h): i + 1 for i, h in enumerate(headers) if h}
+    for need in ("Trade_ID", "Source_Origin", "Ticker", "Record_Date"):
+        if need not in col:
+            print(f"FAIL: missing header {need}")
+            return 1
+
+    rows = []
+    for r in range(3, ws.max_row + 1):
+        tid = ws.cell(r, col["Trade_ID"]).value
+        if tid in (None, ""):
+            continue
+        src = str(ws.cell(r, col["Source_Origin"]).value or "").strip()
+        rows.append((str(tid).strip(), src))
+
+    counts = Counter(src for _, src in rows)
+    dup = len(rows) - len({tid for tid, _ in rows})
+    print(f"OK data_rows={len(rows)} replay={counts.get('REPLAY_BACKFILL_KRX_EOD', 0)} gas={counts.get('GAS_AUTO', 0)} dup_trade_id={dup}")
+    if dup > 0:
+        print("FAIL: duplicate trade_id detected")
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())