fix(web): switch i18n.ts to await requestLocale (next-intl 3.22+)

The `locale` parameter passed to getRequestConfig is deprecated; next-intl
now provides `requestLocale` as a Promise. Resolve it at the top of the
callback, fall back to defaultLocale when the requested one isn't supported,
and return both locale and messages.

Removes the per-request deprecation warning in dev/E2E logs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/i18n.ts

@@ -1,4 +1,3 @@
-import { notFound } from 'next/navigation';
 import { getRequestConfig } from 'next-intl/server';
 
 export const locales = ['it'] as const;
@@ -6,13 +5,14 @@ export const defaultLocale = 'it' as const;
 
 export type Locale = (typeof locales)[number];
 
-export default getRequestConfig(async ({ locale }) => {
-  if (!locales.includes(locale as Locale)) {
-    notFound();
-  }
+export default getRequestConfig(async ({ requestLocale }) => {
+  const requested = await requestLocale;
+  const locale: Locale = locales.includes(requested as Locale)
+    ? (requested as Locale)
+    : defaultLocale;
 
   return {
-    locale: locale as Locale,
+    locale,
     messages: (await import(`../messages/${locale}.json`)).default,
   };
 });