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>

services/content/FlatRender.ContentSvc/Models/Requests/Requests.cs

@@ -95,6 +95,14 @@ public record CreateMusicTrackRequest(
     int Sort
 );
 
+public record UpsertRouteRequest(
+    string Slug,
+    string? Name = null,
+    string? Image = null,
+    int Priority = 5,
+    DateTime? LastDate = null
+);
+
 public record UpsertHomeEventRequest(
     string? Title,
     string? Subtitle,