Behavior: Initiates the password reset flow for the specified user account. If the account is active,
a 6-digit verification code is sent to the user's email address. The code should then be submitted to the
reset-password endpoint along with the new password. If the account requires email verification first,
the response LoginStatus will indicate this.

Authorization: Public endpoint — no authentication required.

Side Effects: Sends a password reset email with a 6-digit verification code to the user.

Error Scenarios: Returns 400 if the request is null or UserName is missing. The response LoginStatus indicates
IsPendingEmailConfirmation (4) if the account needs email verification first, IsPendingNewAccountSignup (5) if the account
is not fully registered, or IsDisabled if the account is disabled.