feat: Add user role retrieval, enhance recommended course filtering and detail, and introduce new k6 load tests.

Backend/src/services/user.service.ts

@@ -14,7 +14,8 @@ import {
     updateAvatarRequest,
     updateAvatarResponse,
     SendVerifyEmailResponse,
-    VerifyEmailResponse
+    VerifyEmailResponse,
+    rolesResponse
 } from '../types/user.types';
 import nodemailer from 'nodemailer';
 import { UnauthorizedError, ValidationError, ForbiddenError } from '../middleware/errorHandler';
@@ -212,6 +213,30 @@ export class UserService {
         }
     }
 
+    async getRoles(token: string): Promise<rolesResponse> {
+        try {
+            jwt.verify(token, config.jwt.secret);
+            const roles = await prisma.role.findMany({
+                select: {
+                    id: true,
+                    code: true
+                }
+            });
+            return { roles };
+        } catch (error) {
+            if (error instanceof jwt.TokenExpiredError) {
+                logger.error('JWT token expired:', error);
+                throw new UnauthorizedError('Token expired');
+            }
+            if (error instanceof jwt.JsonWebTokenError) {
+                logger.error('Invalid JWT token:', error);
+                throw new UnauthorizedError('Invalid token');
+            }
+            logger.error('Failed to get roles', { error });
+            throw error;
+        }
+    }
+
     /**
      * Upload avatar picture to MinIO
      */