typemill: No Rate Limiting on Login Endpoint Enables Unlimited Password Brute-Force

Typemill's login endpoint (POST /tm/login, ControllerWebAuth::login()) performs no rate-limiting, failed-attempt counting, or account lockout when captcha is disabled, which is the default configuration. An unauthenticated attacker can send unlimited password-guessing requests against any account, including administrators, with no throttling. The only attempt-counting/lockout logic present in the same file protects an optional secondary email-authcode step and does not apply to the primary password check.