feat(orders): reopen cancelled orders only after confirmation; accurate sales

Cancelled orders:
- Moving an order out of STORNIERT is possible again, but only after a
  warning is confirmed in the status form (OrderStatusForm); without
  the confirmation the server changes nothing.
- Reopening books the counter-entry to the cancellation: goods that the
  cancellation restocked are deducted again (atomically, only if enough
  stock is left, otherwise the order stays cancelled). A later second
  cancellation therefore restocks +1 again instead of leaving +2.
- The warning states that no new payment is collected.

Dashboard figures:
- One definition of a counted sale (lib/sales.ts): not unpaid (NEU),
  not cancelled, no refunded return. Used for revenue today/month, sold
  glasses, average cart, top products/categories, revenue trend and
  repeat customers.
- "Verkaufte Gläser" previously summed every order item, including
  cancelled orders and refunded returns.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

src/app/admin/bestellungen/[id]/page.tsx

@@ -10,6 +10,7 @@ import {
   deleteOrderAction,
 } from "../../actions";
 import { ConfirmForm } from "@/components/confirm-form";
+import { OrderStatusForm } from "@/components/order-status-form";
 import { checkOrderDeletable } from "@/lib/order-delete";
 import { getLocale } from "@/i18n/locale";
 import { getDictionary } from "@/i18n/get-dictionary";
@@ -57,26 +58,15 @@ export default async function AdminOrderDetailPage(props: PageProps<"/admin/best
           </div>
           <p className="text-sm text-ink/65 mt-1">{formatDate(order.createdAt)}</p>
         </div>
-        {/* Storniert ist ein Endzustand (isOrderStatusChangeAllowed) — keine Auswahl anbieten, die der Server ablehnt. */}
-        {order.status !== "STORNIERT" ? (
-        <form action={updateOrderStatusAction} className="flex items-center gap-2">
-          <input type="hidden" name="orderId" value={order.id} />
-          <select
-            name="status"
-            defaultValue={order.status}
-            className="border border-ink/20 bg-background px-3 py-2 text-sm"
-          >
-            {Object.entries(statusLabels).map(([value, label]) => (
-              <option key={value} value={value}>
-                {label}
-              </option>
-            ))}
-          </select>
-          <Button type="submit" className="px-5 py-2.5">
-            {t.adminOrderDetailPage.saveStatus}
-          </Button>
-        </form>
-        ) : null}
+        <OrderStatusForm
+          action={updateOrderStatusAction}
+          orderId={order.id}
+          currentStatus={order.status}
+          labels={statusLabels}
+          saveLabel={t.adminOrderDetailPage.saveStatus}
+          statusAriaLabel={t.adminOrdersPage.statusLabel}
+          reopenConfirmMessage={t.adminOrdersPage.reopenConfirm}
+        />
       </div>
 
       {/* Wo steht die Bestellung? Dieselbe Waben-Zeitleiste wie im Kundenkonto. */}