createWallet/generateWallet/importWallet/newWallet accept an optional
derivationPath template ({index} placeholder) stored in the new
ethereum_wallets.derivation_path column; createAddress/newAddress accept
a one-off override. Presets: PATH_BIP44 (default), PATH_LEDGER_LIVE,
PATH_LEDGER_LEGACY. Backward compatible: parameters appended last, the
column defaults to the standard path, and full-path derivation produces
byte-identical keys to the previous deriveChild implementation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>