feat: Auto-format Authentication Code with Hyphen

In the email, we receive a two-factor authentication code, such as 123-456.

Currently, users can enter the authentication code either as 123456 or 123-456 in the UI, and both formats are accepted. This can cause confusion, as users may not always know whether they should manually input the hyphen.

Expected Behavior:
We would like to implement a feature in the input field where, when the user enters the first three digits (e.g., 123), a hyphen (-) is automatically added after the third digit. This will make the input field more intuitive and eliminate the need for users to manually enter the hyphen.

Proposed Solution:
UI Behavior:

1. As the user types the authentication code, once the input reaches 3 digits, a hyphen (-) should be automatically appended, making it appear as 123-.
2. After the hyphen is added, the user can continue entering the remaining digits (e.g., 456), and the hyphen will remain in place.
3. The final format should be 123-456, and the hyphen should not interfere with the user experience.

No file, entry point, or test is named in the issue. Locate the authentication-code input in the TypeScript UI and inspect its existing handling for both six digits and the 123-456 form; done means typing the first three digits inserts a hyphen, the remaining digits can be entered normally, and the final value is accepted.