/admin now shows only a token field + "Accedi" button on first load —
config and users are structurally in the page but empty/hidden, no data
requested until the token is verified. On successful login (a GET
/admin/config that doesn't 403) it reveals the dashboard and loads
config + users automatically; no more separate "Carica configurazione"/
"Carica utenti" buttons. Token is kept in sessionStorage (cleared on
tab close) so a reload during the same session skips straight back to
the dashboard. Added a Logout button and Enter-to-submit on the token
field.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>