- Lift appUrl/oidcIssuer/oidcClientId/vapidPublicKey into SetupPage so Step2 unmount preserves them - Step2Config now reads/writes these via fields/setFields props - Fastmail app password stays in Step3 local state, never lifted/persisted, cleared on unmount (T-12-15) - Tests: Back from Calendar restores all four Instance values; password not persisted across nav