feat(freight): surface scheduling clock and gate pay during drain

apps/edr-freight-web/backoffice/src/components/bookings/detail/BookingSchedulingWindowCard.tsx

@@ -44,6 +44,27 @@ function formatRelative(iso: string, nowMs: number): string {
   return past ? `${span} ago` : `in ${span}`;
 }
 
+/**
+ * Length of a window as "1h 30m" / "45m". Null unless both ends are real and
+ * ordered — the pay window is configurable per schedule, so this is read off the
+ * actual stamps rather than assuming any fixed duration.
+ */
+function formatDuration(
+  from: string | null | undefined,
+  to: string | null | undefined,
+): string | null {
+  if (!from || !to) return null;
+  const fromMs = new Date(from).getTime();
+  const toMs = new Date(to).getTime();
+  if (!Number.isFinite(fromMs) || !Number.isFinite(toMs)) return null;
+  const minutes = Math.round((toMs - fromMs) / 60_000);
+  if (minutes <= 0) return null;
+  const hours = Math.floor(minutes / 60);
+  const rest = minutes % 60;
+  if (!hours) return `${rest}m`;
+  return rest ? `${hours}h ${rest}m` : `${hours}h`;
+}
+
 function Row({
   label,
   value,
@@ -98,8 +119,18 @@ export function BookingSchedulingWindowCard({
     return () => clearInterval(interval);
   }, []);
 
+  // How long the customer actually had to pay: start → the raw deadline, NOT the
+  // drain end (the drain is settlement grace, not payable time).
+  const windowDuration = formatDuration(
+    booking.selectedForBatchAt,
+    booking.paymentDeadline,
+  );
+
   const hasAnything =
-    Boolean(schedule) || Boolean(payWindowEndsAt) || Boolean(booking.holdExpiresAt);
+    Boolean(schedule) ||
+    Boolean(payWindowEndsAt) ||
+    Boolean(booking.selectedForBatchAt) ||
+    Boolean(booking.holdExpiresAt);
   if (!hasAnything) return null;
 
   const payWindowClosed = payWindowEndsAt
@@ -157,6 +188,18 @@ export function BookingSchedulingWindowCard({
           </Group>
         ) : null}
 
+        {booking.selectedForBatchAt ? (
+          <Row
+            label="Payment window started"
+            value={formatStamp(booking.selectedForBatchAt) ?? "—"}
+            hint={
+              windowDuration
+                ? `${windowDuration} window`
+                : formatRelative(booking.selectedForBatchAt, nowMs)
+            }
+          />
+        ) : null}
+
         {payWindowEndsAt ? (
           <Row
             label="Payment window ends"

apps/edr-freight-web/backoffice/src/types/booking.ts

@@ -206,6 +206,11 @@ export interface BookingDetail {
   trainScheduleStatus?: string | null;
   /** The allocated train's identity + clock, attached by the detail endpoint. */
   trainScheduleSummary?: BookingTrainScheduleSummary | null;
+  /**
+   * When the batch engine picked this booking and opened its pay window — the
+   * start paired with `paymentDeadline` (both are set and cleared together).
+   */
+  selectedForBatchAt?: string | null;
   /** End of this booking's pay window (batch/offer deadline). */
   paymentDeadline?: string | null;
   /**