Adds a "Remember me" checkbox to the login form (single responsive page,
covers mobile + desktop). Unchecked (default) issues the existing
SESSION_DURATION JWT with a browser-session cookie (no maxAge); checked
issues a longer-lived JWT plus a persistent cookie sized by the new
SESSION_DURATION_REMEMBER env var (default 30d). The choice is threaded
through the MFA verify leg so it survives the step-up.
Register/demo logins keep their current persistent behaviour.
jubnl
bf969ee80d