Add Close() for ServerInstance; Fix server's nonce overflow

https://github.com/XTLS/Xray-core/pull/4952#issuecomment-3180075690
5c61142048 (r163855798)

proxy/vless/inbound/inbound.go

@@ -170,6 +170,9 @@ func isMuxAndNotXUDP(request *protocol.RequestHeader, first *buf.Buffer) bool {
 
 // Close implements common.Closable.Close().
 func (h *Handler) Close() error {
+	if h.decryption != nil {
+		h.decryption.Close()
+	}
 	return errors.Combine(common.Close(h.validator))
 }