集群限流是不是不支持limitApp参数？| Cluster flow control by origin

在开启集群限流时，limitApp貌似不起作用，只有在单机限流时才有效果。

是吗?

Start by reproducing the reported difference between cluster flow control and standalone flow control, comparing behavior with and without the limitApp parameter. Read the relevant Sentinel cluster flow-control implementation and documentation, then confirm whether limitApp is expected to work in cluster mode and add a regression test or documentation clarification.

Written by the indexing model from the issue text.