[Task] Remove admin role from user registration

[CotSezer]

Title: [Task] Remove admin role from user registration

Task Description

Update the user registration flow to prevent assigning the ADMIN role during registration. New users must be created without admin role. Ensure role assignment is controlled server-side and cannot be manipulated via client requests.

Acceptance Criteria

• Existing admin users remain unaffected
• API documentation updated to reflect the change

Deadline

16.12.2025

Estimated Workload

15 minutes

Dependencies

• User model / role management implementation
• Registration API endpoint

Reviewer

@enverern

Review Deadline

16.12.2025

Additional Notes

• Validate role assignment exclusively on the backend

[enverern]

Approved and merged the related PR: #536. Issue closed.