add init state & holiday/holiday off

[KimYoonKyum]

Summary

• Add an optional KOSPI top-5 stock ticker line below the news headline, shown during the KRX cash session (Mon–Fri 09:00–15:30 KST) and updated on its own short TTL, independent
  of the news refresh.
• Gate the feature to Korean users: the "show KOSPI ticker?" prompt in newsline init only appears (and can only be enabled) when the effective language is ko; non-ko runs —
  including an explicit --stock on — force it off.
• Fix a first-run gap: if no stock cache exists yet, fetch once regardless of market hours so the ticker isn't blank until the next open.
• Skip weekends entirely (no API calls) and, on market holidays that fall on a weekday, short-circuit via Naver's own marketStatus field once a line is already cached — avoids
  the extra top5 lookup without maintaining a KR holiday calendar.