feat(currency): centralise money formatting + curated currency picker

New `src/lib/utils/currency.ts` is the single source of truth for
display formatting (`formatCurrency`) and the supported-currency
catalog (`SUPPORTED_CURRENCIES`, 10 codes covering the marina market).

New shared components:
- `<CurrencyInput>` — number input with leading symbol prefix and
  decimal inputMode, raw number value out via onChange.
- `<CurrencySelect>` — Select dropdown over `SUPPORTED_CURRENCIES`
  with symbol + code + label per row, replaces the free-text 3-letter
  inputs that let reps type "EURO" or "$$$" into a 3-char ISO column.

Threaded through every money input + display:
- Forms: berth (price/currency), expense (amount/currency), invoice
  (currency Select + line-items unit-price + step-3 review totals).
- Reads: berth-card / berth-columns / invoice-card / expense-card /
  dashboard KPIs / dashboard revenue-forecast / portal-invoices page.
  Each had its own ad-hoc `Intl.NumberFormat` wrapper with slightly
  different fallbacks; collapsed onto the shared helper.

`InvoiceLineItems` gained a `currency` prop so the unit-price input
prefix and the subtotal use the parent invoice's currency rather than
hard-coded `en-US` formatting.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/invoices/invoice-card.tsx

@@ -22,6 +22,7 @@ import {
 } from '@/components/ui/dropdown-menu';
 import { ListCard, ListCardAvatar, ListCardMeta } from '@/components/shared/list-card';
 import { cn } from '@/lib/utils';
+import { formatCurrency } from '@/lib/utils/currency';
 import type { InvoiceRow } from './invoice-columns';
 
 const STATUS_COLORS: Record<string, string> = {
@@ -48,13 +49,7 @@ const STATUS_ACCENT: Record<string, string> = {
   cancelled: 'bg-slate-200',
 };
 
-function formatAmount(total: string, currency: string): string {
-  try {
-    return new Intl.NumberFormat('en', { style: 'currency', currency }).format(Number(total));
-  } catch {
-    return `${currency} ${total}`;
-  }
-}
+const formatAmount = (total: string, currency: string) => formatCurrency(total, currency);
 
 interface InvoiceCardProps {
   invoice: InvoiceRow;