fix: 在 OnConnect 把 mochi 发送配额置 0 规避死锁

internal/broker/hooks.go

@@ -67,6 +67,16 @@ func (h *nixHook) OnConnect(cl *mqtt.Client, pk packets.Packet) error {
 		cl.State.ServerKeepalive = true
 	}
 
+	// B-01：绕开 mochi 发送配额路径（NextImmediate 递归读锁 + PUBACK 配额泄漏）。
+	// ParseConnect 已按客户端 Receive Maximum 设过 sendQuota；此处一律置 0。
+	if cl.State.Inflight != nil {
+		cl.State.Inflight.ResetSendQuota(0)
+	}
+	if rm := pk.Properties.ReceiveMaximum; rm > 0 && rm < 256 {
+		h.b.log.Warn("client receive maximum below 256; server ignores MQTT send quota",
+			"endpoint", endpointID, "receive_maximum", rm)
+	}
+
 	res, err := h.b.auth.Authenticate(context.Background(), endpointID, pk.Connect.Password, remoteIP)
 	if err != nil {
 		st.authErr = err