auto-claude: subtask-1-3 - Add CSRF token generation to middleware

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/middleware.ts

@@ -1,12 +1,45 @@
+import { NextRequest, NextResponse } from 'next/server';
 import createMiddleware from 'next-intl/middleware';
 import { locales, defaultLocale } from './i18n/config';
+import { randomBytes } from 'crypto';
 
-export default createMiddleware({
+const CSRF_TOKEN_COOKIE_NAME = 'csrf_token';
+const CSRF_TOKEN_LENGTH = 32;
+
+const intlMiddleware = createMiddleware({
   locales,
   defaultLocale,
   localePrefix: 'always',
 });
 
+export default function middleware(request: NextRequest) {
+  // Run the i18n middleware first
+  const response = intlMiddleware(request);
+
+  // Check if CSRF token exists in cookies
+  const existingToken = request.cookies.get(CSRF_TOKEN_COOKIE_NAME);
+
+  // Generate and set CSRF token if it doesn't exist
+  if (!existingToken) {
+    const newToken = randomBytes(CSRF_TOKEN_LENGTH).toString('base64url');
+
+    // Create a new response or clone the existing one
+    const finalResponse = response || NextResponse.next();
+
+    finalResponse.cookies.set(CSRF_TOKEN_COOKIE_NAME, newToken, {
+      httpOnly: true,
+      secure: process.env.NODE_ENV === 'production',
+      sameSite: 'strict',
+      maxAge: 60 * 60 * 24, // 24 hours
+      path: '/',
+    });
+
+    return finalResponse;
+  }
+
+  return response;
+}
+
 export const config = {
   matcher: [
     '/',