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/app/radio/leaderboard/page.tsx

@@ -1,3 +1,4 @@
+import { getTranslations } from "next-intl/server";
 import Link from "next/link";
 import { ContentCard, EmptyState, RankBadge } from "@/components/public/ui";
 import { avatarImageUrl } from "@/lib/format";
@@ -38,6 +39,8 @@ async function loadRows(): Promise<{ username: string; look: string; points: num
 }
 
 export default async function RadioLeaderboardPage() {
+  const t = await getTranslations("pages.radioLeaderboard");
+
   const [rows, imagerBase] = await Promise.all([
     loadRows(),
     siteSettings.get("habbo_imaging_url", "https://www.habbo.com/habbo-imaging/avatarimage"),
@@ -47,21 +50,21 @@ export default async function RadioLeaderboardPage() {
     <main style={{ display: "grid", gap: "1.5rem" }}>
       <ContentCard
         icon="🏆"
-        title="Radio Listener Leaderboard"
-        subtitle="Top 50 listeners by points earned tuning in to the radio"
+        title={t("title")}
+        subtitle={t("subtitle")}
       />
 
       <ContentCard padded={rows.length === 0}>
         {rows.length === 0 ? (
-          <EmptyState icon="🏆">No listener points to show yet.</EmptyState>
+          <EmptyState icon="🏆">{t("empty")}</EmptyState>
         ) : (
           <table>
             <thead>
               <tr>
-                <th style={{ width: "3.5rem" }}>Rank</th>
-                <th style={{ width: "3.5rem" }}>Avatar</th>
-                <th>Listener</th>
-                <th style={{ textAlign: "right" }}>Points</th>
+                <th style={{ width: "3.5rem" }}>{t("colRank")}</th>
+                <th style={{ width: "3.5rem" }}>{t("colAvatar")}</th>
+                <th>{t("colListener")}</th>
+                <th style={{ textAlign: "right" }}>{t("colPoints")}</th>
               </tr>
             </thead>
             <tbody>