CVE-2026-91972: Vikunja: Every /api/v2 pre-auth endpoint is unthrottled on a stock install while its /api/v1 twin is rate limited

registerAPIRoutesV2 never applies the unconditional pre-auth rate-limit floor (unauthRateLimit()) to the v2 public routes — it passes that limiter only to /api/v2/ws — and otherwise relies on setupRateLimit, which registers nothing when ratelimit.enabled is false (the default). So on a stock install every v2 pre-auth endpoint (login, register, password-reset token, oauth token) is unthrottled, while its v1 twin is throttled.