feat(admin): affiliate/personal discounts, user-videos, internal routes, authz

Closes the remaining legacy-admin gaps:
- Users «مدیریت» modal: create personal discount or affiliate code (owner_user_id +
  owner_profit_percentage on existing /v1/discounts), and view the user's saved
  projects ("videos") via new admin GET /v1/saved-projects/by-user/{id} (studio)
- Internal routes admin (/admin/routes): CRUD on content.internal_routes
  (RoutesController + CmsService + gateway /v1/routes/*)
- Security: lock identity UsersController Search + Ban to [Authorize(Roles="Admin")]

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

messages/fa.json

@@ -331,7 +331,8 @@
       "stats": "داشبورد",
       "music": "موسیقی",
       "homeEvents": "رویدادهای صفحه اصلی",
-      "comments": "نظرات"
+      "comments": "نظرات",
+      "routes": "مسیرهای داخلی"
     },
     "appAdminNodesPage": {
       "title": "نودهای رندر",