优化leave逻辑

raft.go

@@ -2244,7 +2244,7 @@ func (r *Raft) RemoveNode(nodeID string) error {
 		return fmt.Errorf("leadership transfer in progress")
 	}
 
-	// Cannot remove self
+	// Cannot remove self - return error immediately WITHOUT logging or appending entry
 	if nodeID == r.nodeID {
 		r.mu.Unlock()
 		return fmt.Errorf("cannot remove self from cluster, use TransferLeadership first")