fix(login): allow 2FA retry without losing the password.
Bug: at login, entering a WRONG 2FA code wiped the held password, so even a subsequent CORRECT code failed with 'Incorrect password' and the user had to refresh the page and re-enter their password.
Fix: a wrong 2FA code now keeps the password and stays on the 2FA step, so the user can retry the 6-digit code repeatedly and is let in on a correct one (PinInput resets its own input). Backend login is stateless — no server change needed.
Full Changelog: v44.34...v44.35