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/app.en.yml

@@ -18,6 +18,8 @@ en:
               complexity: "must include at least 3 of: lowercase letters, uppercase letters, numbers and symbols"
         app_announcement:
           no_channel: Select at least one destination (apps, public website or logged-in area).
+          translation_too_long: "Translation %{locale}: a field is too long."
+          translation_invalid_url: "Translation %{locale}: the link must be an http(s) URL."
   club:
     back_to_club: "← Club"
     sport_label: Main sport