Adds RootKey::from_root_xsk_bech32() / from_xprv_bytes() /
to_root_xsk_bech32() so RootKey can ingest + emit the same
bech32 root extended secret key shape that cardano-cli +
cardano-address + the IOG node priv/wallet/<name>/root.prv
file already use. HRP is strictly root_xsk — refuses
acct_xsk/addr_xsk to keep the import scoped to the actual
HD root.
New CLI flag --bootstrap-from-xprv runs an interactive
import: paste root_xsk1... bech32, prompt passphrase,
encrypt, persist as root-xprv.age (parallel to mnemonic.age).
Refuses to overwrite either existing key file (per Cobb's
no-delete-crypto-keys rule — caller has to move aside, not
delete).
Startup path now checks for either mnemonic.age OR
root-xprv.age; refuses if both exist (ambiguous). Same
RootKey downstream — derivation tree, signing, all of it
works identically whether the key came in via mnemonic
or xprv import.
Test root_xprv_round_trip proves the imported xprv derives
to the same address as the mnemonic-imported equivalent.
Kayos
e712f370f0