Add currency settings, Settings service, and dialog to select fiat currency. Add support for non Official currencies like DOGE when using rates.

src/tui/screens/invitations/invitation-import/steps/PreviewInvitationStep.tsx

@@ -42,7 +42,7 @@ export function PreviewInvitationStep({
   onCancel,
   isActive,
 }: PreviewStepProps): React.ReactElement {
-  const { formatSatoshisToFiat } = useSatoshisConversion('USD');
+  const { formatSatoshisToFiat } = useSatoshisConversion();
 
   useLayeredInput('import-flow', (_input, key) => {
     if (key.return) onComplete();