Add .gitignore to prevent accidental key commits

docs: remove faucet from usage, tweak faucet wording

docs: move faucet to its own section after how it works

docs: tweak faucet feature wording

docs: add faucet claim example to usage

docs: add 6-hour cooldown to features and how it works

docs: move faucet into features and how it works sections

docs: shorten faucet note

docs: make faucet a blockquote note under features

docs: reorganize README, give faucet its own section

docs: update faucet URL to permanent Cloudflare tunnel

Update README.md

fix: sendall uses manual tx building to avoid TxBuilder fee issues

feat: add sendall command to send entire balance minus fee

docs: remove redundant empty wallet language