feat(model): KAP YTM PD floor integration, expanded 226-var search, ADF fix (AIC->BIC), Model#2 with 6-test diagnostics

- Replace hardcoded DEFAULT_PD_FLOORS with build_complete_pd_floor_table() (KAP bond YTM)
- Fix ADF test: autolag='AIC' -> 'BIC' for small sample (N=26) robustness
- Expand variable search: 40 -> 226 vars (log/diff/return/lag2), 1.9M combos
- Select Model #2: HOUSING_PRICE + CREDIT_SPREAD_LAG1 + CURRENT_ACCOUNT_R
- Add 6-test diagnostics table to AR1 sheet (ADF/LB/DW/BP/ARCH/Shapiro)
- Add Korean variable names for transformed variables
- Generate report v7 with full diagnostics

docs/devlog/2026-03-11.md

@@ -9,3 +9,6 @@
 | 5 | 08:00 | 파이프라인 전단계 검증 엑셀 생성 (10시트) | `0e1e0e5` | ✅ |
 | 6 | 15:50 | 시장 YTM PD 플로어 + WR보정 + 7x7 전이행렬 파싱 | `b8514c1` | ✅ |
 | 7 | 16:20 | 7x7 Zt추정 + CCC보간(8x8) + main.py 연결 + 50Y PD검증(8/8통과) + 문서/Wiki | `2b94cc8`~`8a0d6e7` | ✅ |
+| 8 | 21:57 | KAP 채권 YTM 기반 PD Floor 실계산 적용 (build_complete_pd_floor_table) | - | ✅ |
+| 9 | 22:30 | 확장 변수 탐색 226개 (log/diff/return/lag2), 192만 조합. ADF 수정(AIC->BIC) | - | ✅ |
+| 10 | 23:47 | Model #2 선택 (주택가격+신용스프레드+경상수지변화율), 6개 검정 진단표 보고서 | - | ✅ |