Add COD-in-transit summary and received tab to the dashboard

- GET /orders/summary: count and sum of cash-on-delivery for parcels not
  yet picked up (excludes received, refused, deleted/unknown TTNs, paid COD);
  shown as a card above the tabs.
- New «Полученные» tab: orders with NP received codes (9, 10, 11, 106) move
  there automatically, regardless of receipt; 106 is now a final status.

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

frontend/src/api/orders.ts

@@ -1,10 +1,14 @@
 import { apiFetch } from '@/api/client'
-import type { Order, OrderTab, OrderUpdate } from '@/features/orders/types'
+import type { Order, OrdersSummary, OrderTab, OrderUpdate } from '@/features/orders/types'
 
 export function getOrders(tab: OrderTab): Promise<Order[]> {
   return apiFetch<Order[]>(`/orders?tab=${tab}`)
 }
 
+export function getOrdersSummary(): Promise<OrdersSummary> {
+  return apiFetch<OrdersSummary>('/orders/summary')
+}
+
 export function deleteOrder(orderId: string): Promise<void> {
   return apiFetch<void>(`/orders/${orderId}`, { method: 'DELETE' })
 }