Prompt Freighter to sign transactions as a JS dapp developer

If you're building a JS dapp, easily sign Soroban transactions using the Freighter browser extension and its corresponding client library @stellar/freighter-api:

1. Follow the setup instructions to connect to the Testnet, if required during development.

2. Now, you can use the signTransaction method from @stellar/freighter-api in your dapp to sign Soroban XDRs using the account in Freighter.

3. Upon calling signTransaction, Freighter will open and prompt the user to sign the transaction. Approving the transaction will return the signed XDR to the requesting dapp.