feat(billing): 平台订单创建页展示订阅关联提示并加测试

app/Http/Controllers/Admin/PlatformOrderController.php

@@ -7,6 +7,7 @@ use App\Http\Controllers\Controller;
 use App\Models\Merchant;
 use App\Models\Plan;
 use App\Models\PlatformOrder;
+use App\Models\SiteSubscription;
 use App\Support\SubscriptionActivationService;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Http\RedirectResponse;
@@ -39,9 +40,16 @@ class PlatformOrderController extends Controller
             'remark' => (string) $request->query('remark', ''),
         ];
 
+        $siteSubscription = null;
+        $siteSubscriptionId = (int) ($defaults['site_subscription_id'] ?? 0);
+        if ($siteSubscriptionId > 0) {
+            $siteSubscription = SiteSubscription::query()->with(['merchant', 'plan'])->find($siteSubscriptionId);
+        }
+
         return view('admin.platform_orders.form', [
             'merchants' => $merchants,
             'plans' => $plans,
+            'siteSubscription' => $siteSubscription,
             'billingCycleLabels' => $this->billingCycleLabels(),
             'orderTypeLabels' => $this->orderTypeLabels(),
             'defaults' => $defaults,