aptos: specify payeeAddress requirement

Author: evan-gray

aptos/README.md

@@ -4,6 +4,8 @@ The executor folder was generated with `aptos move init --name executor`.
 
 This module was developed with aptos CLI `7.2.0`. It should generally match the Sui implementation with minor changes necessary for Aptos-specific implementation details.
 
+> 💡 Note: The `payeeAddress` on the signed quote must be registered for `AptosCoin` before being able to receive payments.
+
 ## Development
 
 [Move IDE Plugins](https://aptos.dev/en/build/smart-contracts#move-ide-plugins)