Are you planning on implementing Hardware Wallet support for Ledger and/or Trezor wallets in the future?
Probably, but I haven't implemented 12/24 seed recovery yet. only private keys for now.
Looks nice!
Opensource is a right way to go, I hope you'll create some dev community with this project.
Private keys never leave your device
How could I backup my wallet or restore it? What if I lost or broke my phone?
There's an export feature, so you can backup your private keys in WIF format