Add safety seal support to orders and related logic for wash certificates

- Introduced `safety_seal` column in the `orders` table.
- Updated order creation and completion logic to handle safety seal values.
- Enhanced order and booking classes to manage safety seal attachment and retrieval.
- Added tests to validate safety seal functionality in order processing.

services/nginx/app/tests/Support/Api/ApiFixtures.php

@@ -263,6 +263,7 @@ final class ApiFixtures
             'wash_id' => $attributes['wash_id'] ?? null,
             'lane' => $attributes['lane'] ?? null,
             'po' => $attributes['po'] ?? null,
+            'safety_seal' => $attributes['safety_seal'] ?? null,
             'using_hand_held' => (int)($attributes['using_hand_held'] ?? 0),
             'include_in_invoice' => $attributes['include_in_invoice'] ?? 1,
             'created_at' => $attributes['created_at'] ?? $this->now(),