add SSM note to payments

Author: Simon Goldberg

lib/bitcoin-core/README.md

@@ -229,6 +229,8 @@ curl --user "$BTC_RPC_AUTH" \
 
 This guide covers how to create an encrypted Bitcoin Core wallet specifically designed for receiving and managing payments in a secure and efficient way.
 
+Note: Make sure that you run the following commands after accessing the node via Systems Manager.
+
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 #### **1. Create an Encrypted Payment Wallet**