feat(booth): pay-on-foot at the booth — ticket lookup, pay, exit, voucher, snapshots

Backend: PayStation.lookup (session view + quote in one read); ExitFlow.exitForBooth
reuses the reader path's paid+grace validation (no booth-only unpaid bypass) and
signs vehicle_exit + pulses an exit relay; printExitVoucher reprints the paid ticket
id barcode; site_config.exit_voucher_default (migration 0002) drives the default.
Routes: GET /api/session/:id, POST /api/exit, POST /api/voucher.

Web: BoothPayModal (entry/now/duration/total, tender, 'Printo biletë dalje'),
SnapshotStrip (entry/exit evidence), api.ts client fns, SiteSettings toggle.

apps/web/src/lib/format.ts

@@ -0,0 +1,30 @@
+// Small formatting helpers for the booth. Money is integer MINOR units (never a
+// float — matches the tariff/ledger model); duration is whole minutes.
+
+/** Format integer minor units + ISO-4217 currency as a major-unit string. */
+export function formatMoney(amountMinor: number, currency: string): string {
+  const major = amountMinor / 100;
+  try {
+    return new Intl.NumberFormat(undefined, { style: "currency", currency }).format(major);
+  } catch {
+    // Unknown/garbled currency code — fall back to a plain number + the code.
+    return `${major.toFixed(2)} ${currency}`;
+  }
+}
+
+/** Human duration between two ISO times, e.g. "2h 14m" / "47m" / "0m". */
+export function formatDuration(fromIso: string, toIso: string): string {
+  const ms = Date.parse(toIso) - Date.parse(fromIso);
+  if (!Number.isFinite(ms) || ms < 0) return "—";
+  const mins = Math.floor(ms / 60_000);
+  const h = Math.floor(mins / 60);
+  const m = mins % 60;
+  return h > 0 ? `${h}h ${m}m` : `${m}m`;
+}
+
+/** Local time-of-day HH:MM:SS from an ISO string. */
+export function formatTime(iso: string | null): string {
+  if (!iso) return "—";
+  const d = new Date(iso);
+  return Number.isNaN(d.getTime()) ? "—" : d.toTimeString().slice(0, 8);
+}