REVIEW-001 (M0) L1c/L2s: secrets.session_key was validated and generated by
the wizard but never read by any code path — dead config (KISS).
Remove the field, its validation entry and its generation; the example notes
that a placeholder is replaced at startup in setup mode (M1s) as well as by
the wizard's finish.
Reserved, setup-mode-only, loopback-only: the domain, the top admin, the
authenticator (TOTP), mail/locale — then Finish persists and the dashboard
becomes reachable. The wizard IS the bootstrap (D-026); the TOTP key is
generated at startup so TOTP enrollment precedes Finish (SPEC-009 D-1).