Aggiunge traduzioni it/en/fr/de/es agli avvisi e toglie gli override Android/iOS.

Un avviso ha un testo per lingua; per differenziare le piattaforme si creano due avvisi. L'app riceve già il copy risolto da Accept-Language.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/config/locales/admin.en.yml

@@ -421,18 +421,18 @@ en:
         severity: Severity
         status: Status
         channels: Where to show it
-        channels_hint: Select one or more destinations. Android and iOS are independent. The logged-in area is visible after sign-in (club, teams, account).
+        channels_hint: "Select one or more destinations. Android and iOS are independent: create two notices if the copy should differ. The logged-in area is visible after sign-in (club, teams, account)."
         title: Title
         body: Body
         starts_at: Visible from
         ends_at: Visible until
         window_hint: Leave empty to show immediately while published.
         action_url: Link (optional)
-        action_url_hint: For updates, an empty URL opens that platform's store. Below you can set a different title, body and link for Android and iOS.
+        action_url_hint: For updates, an empty URL opens that platform's store (Play Store on Android, App Store on iOS).
         action_label: Button label
-        android_override: Android only (optional)
-        ios_override: iOS only (optional)
-        platform_override_hint: Leave empty to use the shared title, body and link. Fill in only if this platform should see different copy or a different URL.
+        locales_legend: Copy by language
+        locales_hint: Fill in every app language (Italian, English, French, German, Spanish). Italian is required; missing languages fall back to English, then Italian.
+        locale_required: required
         dismissible: Users can dismiss the notice
         dismissible_hint: Uncheck for maintenance notices that should stay visible.
         submit_create: Save notice