Function qot_market_to_tz 

pub fn qot_market_to_tz(market: i32) -> Tz

Stable API (since v1.4.69) — FTAPI QotMarket 值 → IANA 时区 dispatch。

已知未覆盖：FX_Security / 未知 market 值 → HKT fallback 保证零回归。