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/proposed_AGENTS_constitution_v1.md

@@ -0,0 +1,23 @@
+# AGENTS Constitution Proposal
+
+This proposal extracts the top-level operating principles from `AGENTS.md` without changing the original file.
+
+## Principles
+
+1. No price, quantity, stop, take-profit, or score may be invented by the LLM.
+2. Only registered formula IDs in `spec/13_formula_registry.yaml` may be cited.
+3. `Temp/` files may not be used as runtime source unless explicitly designated as build output.
+4. Canonical artifacts must be read through `canonical_manifest.yaml`.
+5. Replay performance must never be presented as live performance.
+6. Live T+20 sample counts below 30 may not be promoted to `active` or `PASS_100`.
+7. Validation failures may not be bypassed with narrative explanations.
+8. Missing files or missing provenance must be rendered as `DATA_MISSING`.
+9. GAS may not gain new investment decision logic.
+10. Prompts may not request the LLM to calculate prices, quantities, thresholds, or scores.
+11. Failed harness states may not be rendered as executable order tables.
+12. Final decision authority must come from a single canonical execution packet.
+
+## Notes
+
+- This document is a proposal only.
+- The original `AGENTS.md` remains unchanged.