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>

docs/doctrine.md

@@ -0,0 +1,13 @@
+# Doctrine
+
+This repository is a deterministic quant engine.
+
+## Operating Rules
+
+- Numbers are copied from canonical artifacts, not invented in the renderer.
+- `Temp/` is a build/output layer, not a runtime authority.
+- Replay metrics are informational unless explicitly labeled live and sample-qualified.
+- Live T+20 sample counts below 30 cannot unlock `active` or `PASS_100`.
+- GAS is an adapter layer, not a business-logic layer.
+- Prompts are copy-only renderers and must not compute prices, quantities, or thresholds.
+