[Bug]: CUBIC reset_cwnd未重置congestion_recovery_start_time

[qisefengzheng]

What happened?

RFC9002: Appendix B.8 OnPacketsLost
RFC伪代码要求持久拥塞时重置 congestion_recovery_start_time = 0:
if (InPersistentCongestion(pc_lost)):
congestion_window = kMinimumWindow
congestion_recovery_start_time = 0 // <-- 重置recovery时间
xquic Reno正确重置: reno_recovery_start_time = 0 xquic CUBIC未重置: xqc_cubic_reset_cwnd() 不包含 congestion_recovery_start_time = 0
void xqc_cubic_reset_cwnd(void *cong_ctl) {
cubic->epoch_start = 0;
cubic->cwnd = cubic->min_cwnd;
cubic->tcp_cwnd = cubic->min_cwnd;
cubic->last_max_cwnd = cubic->min_cwnd;
// 缺少: cubic->congestion_recovery_start_time = 0;
}

影响: 持久拥塞后CUBIC的recovery状态未被清除，新的ACK可能被错误地认为在recovery期间，导致cwnd无法正常增长

xquic代码位置: xqc_cubic_reset_cwnd() (xqc_cubic.c:222-230)

ngtcp2参考: ngtcp2通过 cc->on_persistent_congestion 回调处理，具体实现在ngtcp2_cc.c中

Steps To Reproduce

Information and Steps to reproduce the behavior.

Relevant log output