NXT 시간외 거래 시간대도 5분 cron 폴링 활성화. 23:30-04:30 dead zone
(KIS 점검) → 04:30 까지 skip. 기존 _seconds_until_next_market_open
(휴장일/주말용) 와 별개로 _seconds_until_nxt_or_market_open 신설.
3 new tests, scheduler suite 11 passed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Time-window dispatcher: pre-market (07:00-09:00, 5min), market
(09:00-15:30, 1min), post-market (15:30-20:00, 5min), overnight skip
to next market day 07:00. Weekend + holiday detection via holidays.json.
Stub holidays.json with 13 dates. Task 6 will sync from
web-backend/stock/app/holidays.json.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
