BTC RPC tunnel scripts for swap testing

Shipped the btc-tunnel.sh family for vanta-desktop. Two parts: an SSH local-forward to a remote bitcoind 's RPC port, and an address-watcher loop that polls for confirmations on a set of P2WPKH addresses without exposing your local node. Pattern that's saved me twice now: never run bitcoind on 0.0.0.0:8332 . Always bind to 127.0.0.1:8332 and SSH-forward. The number of testnet bitcoinds I've seen…