feat(notifications+admin): marketing campaigns

- campaigns table (migration 19) + CRUD + send endpoint in notification-svc
- audience resolution reads cross-schema from identity.users (all / verified /
  with_plan); send dispatches via the SMS or Email channel and logs deliveries
- endpoints: GET/POST /v1/campaigns, POST /v1/campaigns/:id/send, DELETE
- gateway route /v1/campaigns/* → notification
- /admin/marketing: create campaign (channel, audience, template/subject/body),
  list with status + sent counts, send, delete

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

messages/fa.json

@@ -324,7 +324,8 @@
       "media": "رسانه",
       "discounts": "تخفیف‌ها",
       "siteSettings": "تنظیمات سایت",
-      "messaging": "پیام‌رسانی"
+      "messaging": "پیام‌رسانی",
+      "marketing": "بازاریابی"
     },
     "appAdminNodesPage": {
       "title": "نودهای رندر",