update email template

app/Models/Order.php

@@ -18,6 +18,7 @@ class Order extends Model
 
     protected $casts = [
         'date' => 'date',
+        'paid_at' => 'datetime',
     ];
 
     public function customer()
@@ -41,12 +42,18 @@ class Order extends Model
         return $this->hasMany(OrderItem::class, 'order_id');
     }
 
-    /** Invoice generated from this order. */
+    /** First/primary invoice generated from this order (kept for backward compat — an order can have many). */
     public function invoice()
     {
         return $this->hasOne(Invoice::class, 'order_id');
     }
 
+    /** All invoices billed against this order (initial + renewals) — an order can have many. */
+    public function invoices()
+    {
+        return $this->hasMany(Invoice::class, 'order_id');
+    }
+
     // -------------------------------------------------------------------------
     // Helpers
     // -------------------------------------------------------------------------