Add methods to handle user notification preferences and update booking notification logic

- Introduced `wantsSmsNotifications`, `wantsEmailNotifications`, and `getWashCertificateEmail` methods in `users_o`.
- Updated `order_bookings_o` to incorporate user notification preferences for sending SMS and email confirmations.

services/nginx/app/objects/users_o.php

@@ -176,6 +176,34 @@ class users_o extends db
         return false;
     }
 
+    /**
+     * @throws Exception
+     */
+    public function wantsSmsNotifications(): bool
+    {
+        self::requireSelected();
+        return (bool)$this->sms_notifications_enabled->value();
+    }
+
+    /**
+     * @throws Exception
+     */
+    public function wantsEmailNotifications(): bool
+    {
+        self::requireSelected();
+        return (bool)$this->email_notifications_enabled->value();
+    }
+
+    /**
+     * @throws Exception
+     */
+    public function getWashCertificateEmail(): string|null
+    {
+        self::requireSelected();
+        return $this->wash_certificate_email->value();
+    }
+
+
     public function add(string $customer_number, mixed $password, int $role = 0): void
     {
         global $db;