Payslips: format amounts in the org currency

/api/v1/me/payslips items and /api/v1/me/profile now carry the org base
currency. Payslip and Profile read it; the payslips screen formats with
the payslip currency, else the last profile's, else INR. INR output is
unchanged (rupee sign, lakh grouping, no decimals); other currencies show
the ISO code with their own minor units (AED 1,234.50, BHD 1,234.500).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/money.dart

@@ -0,0 +1,18 @@
+import 'package:intl/intl.dart';
+
+/// Formats a payroll amount in the organisation's currency.
+///
+/// [currency] is the ISO 4217 code the server sends on payslips / profile
+/// (`currency`). Missing or blank ⇒ INR, which keeps the original output:
+/// rupee sign, Indian lakh grouping, no decimals (e.g. `₹1,23,457`).
+/// Other currencies print the ISO code and the currency's own minor units
+/// (e.g. `AED 12,345.50`, `BHD 1,234.500`).
+String formatMoney(num v, [String? currency]) {
+  final code = (currency ?? '').trim().toUpperCase();
+  if (code.isEmpty || code == 'INR') {
+    return '₹${NumberFormat('#,##,###').format(v)}';
+  }
+  // NumberFormat.currency picks the ISO default fraction digits for `name`
+  // (BHD/KWD/OMR 3, JPY 0, most others 2).
+  return NumberFormat.currency(locale: 'en', name: code, symbol: '$code ').format(v);
+}