Migrate : Update old API endpoints for new version

[aaryan359]

We have old api end points for the old website. Now, we are moving to the new website so we imorve manyu feature and functionallity so we need more api point for those functions.
checkout old API endpoint: https://github.com/aaryan359/opencoursebackend
Here is a list of api point needed :

Auth

1. POST /api/auth/register → create account
2. POST /api/auth/login → login, return JWT
3. POST /api/auth/logout → logout (optional)
4. GET /api/auth/me → current user profile
5. POST /api/auth/refresh-token → refresh JWT (optional)

User

1. GET /api/users/:id → public user profile
2. PUT /api/users/me → update own profile
3. PUT /api/users/me/password → change password
4. GET /api/users/me/stats → learning stats
5. GET /api/users/me/uploads → videos uploaded by user

Admin:

1. GET /api/admin/users → list users
2. PUT /api/admin/users/:id/role → change role
3. BAN /api/admin/users/:id → block user (optional)