🐛 fix(admin): remove api/v1 prefix from admin controllers

All backends with setGlobalPrefix('api/v1') were registering routes
as /api/v1/api/v1/admin instead of /api/v1/admin. Changed all admin
controllers to use @Controller('admin') instead of @Controller('api/v1/admin').

Affected backends:
- calendar
- contacts
- picture
- presi
- todo
- zitare
- chat

Note: storage backend still uses @Controller('api/v1/admin') as it has
no global prefix.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/chat/apps/backend/src/admin/admin.controller.ts

@@ -17,7 +17,7 @@ import { UserDataResponse, DeleteUserDataResponse } from './dto/user-data-respon
  * Used by mana-core-auth aggregation service
  * Protected by X-Service-Key authentication
  */
-@Controller('api/v1/admin')
+@Controller('admin')
 @UseGuards(ServiceAuthGuard)
 export class AdminController {
 	private readonly logger = new Logger(AdminController.name);