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.
TransactionFactory now selects only confirmed UTXOs (height > 0), so
mempool funds are visible as pending balance but never spendable, with
a clear error when only unconfirmed funds are available. GUI and CLI
labels updated to "in attesa di conferma (non spendibile)".
davide