i18n: translate all public page bodies (EN + IT)

Internationalised the ~44 public pages with next-intl (the shell was
already translated). Each page now pulls its copy from a "pages.<slug>"
namespace via getTranslations (server) / useTranslations (client); the
EN + IT catalogs were authored by parallel agents and merged centrally,
with natural Italian (ICU plurals) and it backfilled from en for any
gap. request.ts gained getMessageFallback/onError so a missing key
degrades to the English value, never a raw key.

Behaviour unchanged (only display text moved to t() calls; queries,
actions, fields, ContentCard structure preserved). Verified on the prod
server: with NEXT_LOCALE=it, home/community/staff/news/shop/rankings all
render Italian copy, no raw-key leakage; English unchanged. The nav
language switcher toggles EN/IT live. tsc 0, vitest 49/49, next build 0.

Admin pages intentionally left in English (staff tooling).

src/i18n/request.ts

@@ -17,8 +17,29 @@ export default getRequestConfig(async () => {
   const cookieLocale = store.get("NEXT_LOCALE")?.value;
   const locale: AppLocale = isSupportedLocale(cookieLocale) ? cookieLocale : DEFAULT_LOCALE;
 
+  const messages = (await import(`../messages/${locale}.json`)).default;
+  // English is the source of truth; fall back to it for any key missing from a
+  // translation so the UI never shows a raw key path.
+  const fallback =
+    locale === DEFAULT_LOCALE
+      ? messages
+      : (await import(`../messages/${DEFAULT_LOCALE}.json`)).default;
+
   return {
     locale,
-    messages: (await import(`../messages/${locale}.json`)).default,
+    messages,
+    // Never throw on a missing message — use the English value, or a humanised
+    // key as a last resort.
+    getMessageFallback({ key }: { key: string }) {
+      const fromEnglish = key
+        .split(".")
+        .reduce<unknown>((o, k) => (o && typeof o === "object" ? (o as Record<string, unknown>)[k] : undefined), fallback);
+      if (typeof fromEnglish === "string") return fromEnglish;
+      const seg = key.split(".").pop() ?? key;
+      return seg.replace(/[._-]/g, " ").replace(/\b\w/g, (c) => c.toUpperCase());
+    },
+    onError() {
+      // Swallow MISSING_MESSAGE etc. — getMessageFallback already degrades.
+    },
   };
 });