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>

backend/tests/test_orders_router.py

@@ -79,6 +79,11 @@ def _patch_orders_service(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(orders_router.orders_service, "list_orders", fake_list)
     monkeypatch.setattr(orders_router.orders_service, "delete_order", fake_delete)
 
+    async def fake_cod_in_transit(session: object) -> tuple[int, int]:
+        return 3, 245050
+
+    monkeypatch.setattr(orders_router.orders_service, "cod_in_transit", fake_cod_in_transit)
+
     async def fake_update(
         session: object, order_id: str, data: object
     ) -> tuple[Order, list[str]] | None:
@@ -238,3 +243,17 @@ class TestUpdateOrder:
         response = client.patch("/api/v1/orders/1", json={**_UPDATE_BODY, "goods": []})
 
         assert response.status_code == 422
+
+
+class TestSummary:
+    @pytest.mark.parametrize("role", [UserRole.ADMIN, UserRole.CASHIER, UserRole.VIEWER])
+    def test_returns_cod_in_transit(self, client: TestClient, role: UserRole) -> None:
+        app.dependency_overrides[get_current_user] = lambda: _user(role)
+
+        response = client.get("/api/v1/orders/summary")
+
+        assert response.status_code == 200
+        assert response.json() == {
+            "cod_in_transit_count": 3,
+            "cod_in_transit_amount": "2450.50",
+        }