feat(admin): 仪表盘补齐订阅到期治理入口（7天内到期/已过期）

app/Http/Controllers/Admin/DashboardController.php

@@ -38,6 +38,15 @@ class DashboardController extends Controller
                 // 收费中心（平台侧）
                 'plans' => Plan::count(),
                 'site_subscriptions' => SiteSubscription::count(),
+                'site_subscriptions_expired' => SiteSubscription::query()
+                    ->whereNotNull('ends_at')
+                    ->where('ends_at', '<', now())
+                    ->count(),
+                'site_subscriptions_expiring_7d' => SiteSubscription::query()
+                    ->whereNotNull('ends_at')
+                    ->where('ends_at', '>=', now())
+                    ->where('ends_at', '<', now()->addDays(7))
+                    ->count(),
                 'platform_orders' => PlatformOrder::count(),
                 'platform_orders_unpaid_pending' => PlatformOrder::query()
                     ->where('payment_status', 'unpaid')