Add global AppConfig (config.json, blueprint §8) persisting language
and amount unit. CoinAmount gains unit-aware formatting and parsing
(PLM, mPLM, µPLM, sat), applied everywhere amounts are shown or
entered, including the send form. New Loc i18n layer (it/en) with
live-updating XAML bindings covering menu, wizard, wallet panel and
status messages.
The Impostazioni menu opens a dropdown with separate Lingua and Unità
entries (radio-checked submenus, applied and saved on click), ready to
host future settings.
Startup now follows the blueprint §15 flow, one field per screen with
Avanti/Indietro: initial choice (open / create / restore), seed display
with write-it-down warning, seed confirmation by re-typing, mnemonic
validation on restore, optional BIP39 passphrase, and wallet file
password as the final step. Opening an encrypted file from the menu
routes to the same password step.
davide