Integrated chronik's broadcastTx post method into the sendXec()'s tx broadcasting logic. The transaction builder portion is still using bch-js for now until I review Sam Rock's XEC fork of bch-js that natively supports ecash addresses.

Lessons learnt include:

• it's not necessary to spin up a https dev instance of cashtab to access chronik post methods, as the network errors encountered to date were just a server side COR policy config, which have now been resolved.
• no need to convert bitcoincash addresses back into ecash to interact with chronik's broadcastTx method, although we will eventually refactor the useBCH hook to use a fork of bch-js that can take in ecash addresses directly via TransactionBuilder.

TODO: as per telegram, further discussion needed on mocking chronik calls for the following unit tests in useBCH.test.js:

• sends XEC correctly
• sends XEC correctly with an encrypted OP_RETURN message
• sends one to many XEC correctly
• receives errors from the network and parses it

• npm start
• verify successful onchain broadcast of the following:

send a 1-to-1 XEC transaction
send a 1-to-1 XEC transaction with an OP_RETURN msg
send a 1-to-1 encrypted XEC transaction
send a 1-to-many XEC transaction
send a 1-to-many XEC transaction with an OP_RETURN msg

• verify no cross browser issues across chrome/brave/firefox
• verify no chronik issues when executing the above in extension plugin mode
• verify no chronik issues when executing the above on iOS/Android mobile

iOS/Android test build via https://1154.netlify.app