feat(warehouses): approve-delivery opens handover doc for review and signing

Customer reviews the generated handover before signing:
- add booking-scoped handover-document endpoint (portal only has bookingId)
- ApproveDeliveryModal renders the handover PDF, then applies the customer's
  saved signature on approve and returns the signed PDF
- ApproveDeliveryButton opens the modal instead of one-click silent signing

Handover generation + sign notification (in-app + SMS + email) and the
"Approve delivery" visibility on an awaiting-signature handover were committed
earlier; this wires the review-and-sign step.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/edr-freight-web/portal/src/services/api.ts

@@ -264,6 +264,13 @@ export const api = {
         bookingsService.downloadHandoverDocument(inventoryId),
     ),
 
+    downloadBookingHandoverDocument: endpoint<{ bookingId: string }, Blob>(
+      "bookings",
+      "downloadBookingHandoverDocument",
+      ({ bookingId }) =>
+        bookingsService.downloadBookingHandoverDocument(bookingId),
+    ),
+
     create: endpoint<
       { payload: CreateBookingPayload; documents?: BookingDocuments },
       Freight.IBooking