Constant CRYPTO_SUPPORTED_MAIN_BROKER_CANDIDATES 

pub const CRYPTO_SUPPORTED_MAIN_BROKER_CANDIDATES: &[u32];

当前 QOT crypto 行情支持 broker_id 候选集 (C++ 协议常量, broker_market_svr.cpp:50-68). 与 qot_security_firm_to_broker_id 形成闭环: firm 1/2/3 → broker 1001/1007/1008.