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/berths/berth-columns.tsx

@@ -12,6 +12,7 @@ import {
   DropdownMenuTrigger,
 } from '@/components/ui/dropdown-menu';
 import { TagBadge } from '@/components/shared/tag-badge';
+import { formatCurrency } from '@/lib/utils/currency';
 import { mooringLetterDot } from './mooring-letter-tone';
 
 export type BerthRow = {
@@ -176,11 +177,7 @@ function joinNonNull(parts: Array<string | null | undefined>, sep = ' · '): str
 
 function formatMoney(amount: string | null, currency: string): string | null {
   if (!amount) return null;
-  return new Intl.NumberFormat('en-US', {
-    style: 'currency',
-    currency: currency || 'USD',
-    maximumFractionDigits: 0,
-  }).format(Number(amount));
+  return formatCurrency(amount, currency, { maxFractionDigits: 0 });
 }
 
 export const berthColumns: ColumnDef<BerthRow, unknown>[] = [