feat(admin): star/tags marks, service product-type filter, campaign bulk actions, SMTP test

- Star (is_starred) and colored tags for services, customers, orders, invoices:
  Markable trait, tags/taggables tables, PATCH administrator/marks/{type}/{key},
  tag CRUD, list filters starred / tag_ids[]
- GET administrator/services accepts product_type (falls back to product type
  for legacy rows without services.type)
- Mail campaigns: bulk cancel / retry failed / delete; cancelled campaigns are
  skipped by SendMailCampaignRecipient
- POST administrator/settings/test-smtp sends a test email through the saved
  mail transport

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/Http/Controllers/Api/Admin/Invoice/InvoiceController.php

@@ -49,6 +49,7 @@ class InvoiceController extends Controller
                 'customer',
                 'order',
                 ...OrderItemServiceResource::relationsFor('order.orderItems'),
+                'tags',
             ],
             [],
             ['*'],