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/register/page.tsx

@@ -1,4 +1,5 @@
 import Link from "next/link";
+import { getTranslations } from "next-intl/server";
 import { register } from "@/actions/register";
 import { ContentCard } from "@/components/public/ui";
 
@@ -7,27 +8,28 @@ export default async function RegisterPage({
 }: {
   searchParams: Promise<{ error?: string }>;
 }) {
+  const t = await getTranslations("pages.register");
   const { error } = await searchParams;
 
   return (
     <main style={{ maxWidth: 420, margin: "2rem auto" }}>
       <ContentCard
         icon="🎉"
-        title="Create account"
-        subtitle="Join the hotel — it only takes a moment."
+        title={t("title")}
+        subtitle={t("subtitle")}
       >
         <form action={register} style={{ display: "grid", gap: "0.7rem" }}>
-          <input name="username" placeholder="Username" autoComplete="username" required />
-          <input name="mail" type="email" placeholder="Email" autoComplete="email" required />
+          <input name="username" placeholder={t("usernamePlaceholder")} autoComplete="username" required />
+          <input name="mail" type="email" placeholder={t("emailPlaceholder")} autoComplete="email" required />
           <input
             name="password"
             type="password"
-            placeholder="Password (min 6 chars)"
+            placeholder={t("passwordPlaceholder")}
             autoComplete="new-password"
             required
           />
           <button type="submit" className="btn btn-primary">
-            Register
+            {t("register")}
           </button>
         </form>
         {error ? (
@@ -36,7 +38,7 @@ export default async function RegisterPage({
           </p>
         ) : null}
         <p className="muted" style={{ textAlign: "center", marginBottom: 0, marginTop: "1rem" }}>
-          Already have an account? <Link href="/login">Sign in</Link>
+          {t("alreadyHaveAccount")} <Link href="/login">{t("signIn")}</Link>
         </p>
       </ContentCard>
     </main>