Implement User Profile Management

[Ram-Raghav-S]

Description: Allow authenticated users to view and update their profile information, including first name, last name, email, avatar, and phone number.

Acceptance Criteria:

• Users can fetch their profile information.
• Users can update their profile details securely.
• Email updates handle uniqueness constraints.
• Avatar upload is optional for Part 1 but structured for future implementation.
• Profile management endpoints are tested and documented.

[Ram-Raghav-S]

Could be blocked by: https://github.com/Scriptorium-CSC309/web/issues/5