Move the radio on/off switch out of renderer-config (where it sat next
to asset/data URLs) into ui-config, alongside the other UI feature
toggles (game.center.enabled, guides.enabled, …) — the natural home for
a widget switch — and rename it to the dotted convention `radio_ui.enabled`.
The MainView gate now defaults to `false`, so the radio is opt-in: an
absent key keeps it hidden; set `"radio_ui.enabled": true` in ui-config
to show it. The radio.url data source stays in renderer-config.
Aggiunge un checkbox nelle impostazioni utente per scegliere lo stile del
catalogo (classico vs moderno) + flag globale catalog.classic.style in
ui-config.json come default per tutti. Override per-utente in localStorage.
simoleo89