[FEATURE] Don't login if the user is already logged in

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

/login starts the login flow regardless of the user authentication status

Proposed Solution

When /login is invoked but the user is already authenticated, show a message like "Already logged in. Sign In again?" instead of starting the login flow.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_