fix(web): wire up next-intl i18n — install dep, add locale middleware, wrap next config

The i18n architecture (config, routing, translation files, locale pages) was
already built but non-functional due to three missing pieces:
1. next-intl not listed in package.json
2. middleware.ts not using createMiddleware from next-intl/middleware
3. next.config.js not wrapped with createNextIntlPlugin

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/middleware.ts

@@ -1,32 +1,45 @@
 import { NextResponse, type NextRequest } from 'next/server';
+import createIntlMiddleware from 'next-intl/middleware';
+import { routing } from '@/i18n/routing';
+
+const intlMiddleware = createIntlMiddleware(routing);
 
 const publicPaths = ['/login', '/register', '/search', '/auth/callback'];
-
 const publicExactPaths = ['/'];
+const authOnlyPaths = ['/login', '/register'];
+
+function isPublicPath(pathname: string): boolean {
+  return (
+    publicExactPaths.includes(pathname) ||
+    publicPaths.some((path) => pathname.startsWith(path))
+  );
+}
+
+function stripLocale(pathname: string): string {
+  const localePattern = /^\/(vi|en)(\/|$)/;
+  return pathname.replace(localePattern, '/') || '/';
+}
 
 export function middleware(request: NextRequest) {
   const { pathname } = request.nextUrl;
+  const strippedPath = stripLocale(pathname);
 
-  const isPublicPath =
-    publicExactPaths.includes(pathname) ||
-    publicPaths.some((path) => pathname.startsWith(path));
-
-  // We check for the token cookie or rely on client-side auth store.
-  // For SSR-safe auth, check a lightweight cookie set by the client after login.
   const hasAuthCookie = request.cookies.has('goodgo_authenticated');
 
-  if (!isPublicPath && !hasAuthCookie) {
+  if (!isPublicPath(strippedPath) && !hasAuthCookie) {
     const loginUrl = new URL('/login', request.url);
-    loginUrl.searchParams.set('redirect', pathname);
+    loginUrl.searchParams.set('redirect', strippedPath);
     return NextResponse.redirect(loginUrl);
   }
 
-  const isAuthOnlyPath = ['/login', '/register'].some((path) => pathname.startsWith(path));
-  if (isAuthOnlyPath && hasAuthCookie) {
+  const isAuthOnly = authOnlyPaths.some((path) =>
+    strippedPath.startsWith(path),
+  );
+  if (isAuthOnly && hasAuthCookie) {
     return NextResponse.redirect(new URL('/dashboard', request.url));
   }
 
-  return NextResponse.next();
+  return intlMiddleware(request);
 }
 
 export const config = {

apps/web/next.config.js

@@ -1,4 +1,7 @@
 const { withSentryConfig } = require('@sentry/nextjs');
+const createNextIntlPlugin = require('next-intl/plugin');
+
+const withNextIntl = createNextIntlPlugin('./i18n/request.ts');
 
 /** @type {import('next').NextConfig} */
 const nextConfig = {
@@ -44,7 +47,7 @@ const nextConfig = {
   },
 };
 
-module.exports = withSentryConfig(nextConfig, {
+module.exports = withSentryConfig(withNextIntl(nextConfig), {
   org: process.env.SENTRY_ORG,
   project: process.env.SENTRY_PROJECT,
   silent: !process.env.CI,

apps/web/package.json

@@ -19,6 +19,7 @@
     "lucide-react": "^1.7.0",
     "mapbox-gl": "^3.21.0",
     "next": "^14.2.0",
+    "next-intl": "^4.9.0",
     "react": "^18.3.0",
     "react-dom": "^18.3.0",
     "react-hook-form": "^7.72.1",