fix(price-trigger): store the selected product instead of defaulting to gold

Only a real numeric product id is saved, and an empty alert title no longer falls back to gold.

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

app/Services/PriceTriggerService.php

@@ -160,7 +160,10 @@ class PriceTriggerService
     {
         $title = trim((string) ($product?->title ?? ''));
         if ($title === '') {
-            $title = 'طلا';
+            $title = trim((string) app(ConfigService::class)->getString('metal_type', ''));
+        }
+        if ($title === '') {
+            $title = 'محصول';
         }
 
         $shopName = (string) app(ConfigService::class)->getString('name_fa');