fix: harden next.config rewrites against wrapper overwrites

apps/web/next.config.mjs

@@ -14,7 +14,7 @@ const nextConfig = {
     'sharp',
     'puppeteer',
     'require-in-the-middle',
-    'import-in-the-middle' // Sentry 10+ instrumentation dependencies
+    'import-in-the-middle'
   ],
   transpilePackages: [
     '@mintel/content-engine',
@@ -37,9 +37,42 @@ const nextConfig = {
       },
     ],
   },
-  async rewrites() {
+  async redirects() {
+    return [
+      {
+        source: '/case-studies/klz',
+        destination: '/case-studies/klz-cables',
+        permanent: true,
+      },
+    ];
+  },
+  outputFileTracingRoot: path.join(dirname, '../../'),
+};
+
+const withMDX = createMDX({});
+
+// Apply wrappers
+const wrappedConfig = withPayload(withMintelConfig(withMDX(nextConfig)));
+
+// HARDEN REWRITES: Manually merge showcase rules to prevent wrapper overwrites
+const originalRewrites = wrappedConfig.rewrites;
+wrappedConfig.rewrites = async () => {
+  const existing = await originalRewrites?.() || [];
+  
+  // Normalize existing to object pattern (Next.js supports both Array and Object)
+  const normalized = Array.isArray(existing) 
+    ? { afterFiles: existing, beforeFiles: [], fallback: [] } 
+    : existing;
+
   return {
+    ...normalized,
     beforeFiles: [
+      ...(normalized.beforeFiles || []),
+      // Diagnostic rule
+      {
+        source: '/robots-test',
+        destination: '/robots.txt',
+      },
       // Assets requested from root
       {
         source: '/assets/:path*',
@@ -66,27 +99,8 @@ const nextConfig = {
         source: '/:folder(case-studies|work|blog)/wp-includes/:path*',
         destination: '/showcase/klz-cables.com/assets/klz-cables.com/wp-includes/:path*',
       },
-        // Diagnostic rule
-        {
-          source: '/robots-test',
-          destination: '/robots.txt',
-        },
     ],
   };
-  },
-  async redirects() {
-    return [
-      {
-        source: '/case-studies/klz',
-        destination: '/case-studies/klz-cables',
-        permanent: true,
-      },
-    ];
-  },
-  outputFileTracingRoot: path.join(dirname, '../../'),
 };
 
-const withMDX = createMDX({
+export default wrappedConfig;
-  // Add markdown plugins here, as desired
-});
-export default withPayload(withMintelConfig(withMDX(nextConfig)));