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/redeem/page.tsx

@@ -1,3 +1,4 @@
+import { getTranslations } from "next-intl/server";
 import { redirect } from "next/navigation";
 import RedeemForm from "./RedeemForm";
 import { ContentCard, StatBlock } from "@/components/public/ui";
@@ -10,6 +11,7 @@ export default async function RedeemPage() {
   const session = await auth();
   if (!session?.user?.id) redirect("/login");
 
+  const t = await getTranslations("pages.redeem");
   const id = Number(session.user.id);
 
   // Show the signed-in user's current credit balance for context (fail soft).
@@ -29,24 +31,28 @@ export default async function RedeemPage() {
     <main style={{ display: "grid", gap: "1.5rem" }}>
       <ContentCard
         icon="🎟️"
-        title="Redeem a voucher"
-        subtitle="Got a voucher code? Enter it below to add the reward to your account."
+        title={t("title")}
+        subtitle={t("subtitle")}
       />
 
       <div className="card-grid sm-2">
-        <ContentCard icon="🔑" title="Enter your code">
+        <ContentCard icon="🔑" title={t("enterCode")}>
           <RedeemForm />
           <p className="muted" style={{ marginBottom: 0, marginTop: "0.85rem" }}>
-            Each voucher can only be redeemed once per account.
+            {t("oncePerAccount")}
           </p>
         </ContentCard>
 
-        <ContentCard icon="💰" title="Your balance" subtitle={`Signed in as ${user.username}`}>
+        <ContentCard
+          icon="💰"
+          title={t("balanceTitle")}
+          subtitle={t("signedInAs", { username: user.username })}
+        >
           <div className="stat-grid">
-            <StatBlock value={user.credits.toLocaleString()} label="Credits" icon="🪙" />
+            <StatBlock value={user.credits.toLocaleString()} label={t("credits")} icon="🪙" />
           </div>
           <p className="muted" style={{ marginBottom: 0, marginTop: "0.85rem" }}>
-            Redeemed rewards are credited instantly and appear in-game the next time you log in.
+            {t("instantCredit")}
           </p>
         </ContentCard>
       </div>