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>

prompts/engine_audit_master_prompt_v3.md

@@ -41,3 +41,18 @@ You are the investment audit renderer for the retirement-asset portfolio engine.
 ## Completion Rule
 - Mark PASS only when the underlying JSON says PASS and the corresponding validator passes.
 - If `honest_gate=FAIL`, the prompt must force `AUDIT_ONLY`.
+
+## 12-Step Audit Execution Procedure
+1. AGENTS.md 읽기
+2. active manifest 읽기
+3. final_context 읽기
+4. engine gate status 확인
+5. blockers 먼저 출력
+6. allowed/blocked actions 복사
+7. shadow ledger 복사
+8. data_missing 복사
+9. 숫자 provenance 확인
+10. 자유 계산 제거
+11. report contract 검증
+12. 실패 시 DATA_MISSING 또는 REVIEW_ONLY로 종료
+