fix(admin): stop dashboard OOM by aggregating product stats in SQL

Drop unbounded TransactionsAdmin/customer dumps from dashboardMaster
and aggregate GT_products_report without loading all transactions.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Http/Controllers/Admin/DashboardController.php

@@ -9,7 +9,6 @@ use App\Models\Order;
 use App\Models\Price;
 use App\Models\Product;
 use App\Models\ProfitConversion;
-use App\Models\TransactionsAdmin;
 use App\Models\Withdraw;
 use App\Services\BalanceReportService;
 use App\Services\ConfigService;