白宫枪击事件：已知信息汇总

• 输出包含未在情报源/系统注入中出现的精确价格，已脱敏以避免价格幻觉

1. 核心事实剥离

• 事件本质：一名枪手于华盛顿时间18:00前后在白宫附近向特勤局特工开枪未遂，特勤局还击并击伤枪手及一名旁观者，白宫即刻封锁。〔SRC:"At around 18:00 local time (23:00 GMT), a volley of gunfire was heard by multiple journalists who were present at the White House" + "a