fix: data_gaps_roadmap status update - S3 DONE, S5 DATA_GATED

S3_sector_flow_weekly_history: LEGACY_INTERIM -> DONE
  (Prev_Rotation_Rank W1/W2 legacy interim 구현 완료)
S5_etf_raw_execution_quality: PARTIAL_DONE_WITH_MANUAL_NAV -> DATA_GATED
  (NAV/iNAV/AUM 자동수집은 KRX/KIND API 경로 확정 필요)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

spec/16_data_gaps_roadmap.yaml

@@ -117,7 +117,7 @@ phase_2_structural:
 
   S3_sector_flow_weekly_history:
     priority: MEDIUM
-    status: LEGACY_INTERIM
+    status: DONE
     implementation: >
       option_B legacy interim 구현 완료 (2026-05-17).
       sector_flow 탭에 Prev_Rotation_Rank(W1), Prev_Rotation_Rank_W2 컬럼 추가.
@@ -148,7 +148,7 @@ phase_2_structural:
 
   S5_etf_raw_execution_quality:
     priority: HIGH
-    status: PARTIAL_DONE_WITH_MANUAL_NAV
+    status: DATA_GATED
     implementation: >
       2026-05-17 Phase 3 interim 구현.
       etf_raw 시트를 신설하고 ETF proxy/ETF 구성행에 대해 Close, Bid, Ask, Spread_Pct,