feat: enhance CORS configuration and implement throttling for API endpoints; add admin role checks in controllers

backend/src/receipt-alias/receipt-alias.controller.ts

@@ -1,7 +1,9 @@
 import { Body, Controller, Delete, Get, Param, ParseIntPipe, Post } from '@nestjs/common';
 import { ReceiptAliasService } from './receipt-alias.service';
 import { CreateReceiptAliasDto } from './dto/create-receipt-alias.dto';
+import { Roles } from '../auth/decorators/roles.decorator';
 
+@Roles('admin')
 @Controller('receipt-aliases')
 export class ReceiptAliasController {
   constructor(private readonly receiptAliasService: ReceiptAliasService) {}