Feature: Add Role-Based User Authentication (Alumni, Students, Administrators)

**Description**
Introduce a secure authentication system to the alumni portal that supports multiple user roles. The feature should allow alumni, students, and administrators to log in with different levels of access and permissions.

**Why This Feature Is Needed**

* Secure access control is fundamental for any portal handling personal and community data.
* Different user groups (alumni, students, admins) need distinct access rights and functionality.
* Without authentication, the portal cannot be scaled to production use.

**Proposed Solution**

* Implement a user authentication system (e.g., JWT-based or session-based login).
* Add role-based access control (RBAC) with permissions defined for each role.
* Store user credentials securely (password hashing, salted).

**Expected Outcome**

* Secure login and signup workflows.
* Role-specific dashboards.
* Improved trust and usability of the portal.

Hi, I would like this task to be assigned to me as i have prior experience in building authentication.