WBS-7.3: GAS→Python 마이그레이션 5개 항목 완료 (F14, F02-F06)

- F14: late_chase_risk_score 검증
  * GAS가 유일한 생산처 (Python canonical 없음)
  * migration_action: KEEP_IN_GAS로 정정, status: DONE

- F02/F03/F04/F06: priceBasis 로직 포팅
  * formulas/price_basis_v1.py: select_price_basis_tier2/tier1 구현
  * tests/parity/test_price_basis_parity_v1.py: 8 parity 테스트 (모두 PASS)
  * GAS Number.isFinite() 의미론 정확히 재현 (math.isfinite 사용)
  * 모든 테스트 112/112 PASS

남은 작업 (4개):
- F05: decision_logic (action assignment)
- F07: score_logic (threshold addition)
- F10: routing decision
- F15: late_chase_gate

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

RetirementAssetPortfolio.yaml

@@ -68,6 +68,7 @@ source_of_truth_order:
   7c: "spec/factor_lifecycle_registry.yaml — factor lifecycle status core/retired classification"
   8: "spec/14_raw_workbook_mapping.yaml — market raw JSON path/column mapping"
   9: "spec/15_account_snapshot_contract.yaml — image capture account/holding/cash contract"
+  9b: "spec/gas_adapter_contract.yaml — Apps Script exported function sheets and arities contract"
   10: "spec/19_harness_contract.yaml — deterministic harness contract, lock semantics, sync validation"
   10b: "spec/20_harness_output_schema.yaml — mandatory numeric output schema; GAS coverage measurement baseline"
   10c: "spec/21_harness_governance_contract.yaml — harness governance 3-layer lock and release hardlocks"
@@ -114,6 +115,7 @@ load_sequence:
       - "spec/13b_harness_formulas.yaml"
       - "spec/14_raw_workbook_mapping.yaml"
       - "spec/15_account_snapshot_contract.yaml"
+      - "spec/gas_adapter_contract.yaml"
       - "spec/19_harness_contract.yaml"
       - "spec/20_harness_output_schema.yaml"
       - "spec/21_harness_governance_contract.yaml"