perf: fix PageSpeed Insights issues (WebGL errors, bfcache, redirects, a11y)

- Add WebGL support detection in ShaderGradientBackground to prevent console errors
- Add .catch() fallback to ShaderGradientBackground dynamic import
- Remove hardcoded aria-label from consent banner minimize button (fixes label-content-name-mismatch)
- Use rewrite instead of redirect for root locale routing (eliminates one redirect hop)
- Change n8n API cache headers from no-store to no-cache (enables bfcache)
- Add three and @react-three/fiber to optimizePackageImports for better tree-shaking

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

app/components/ClientProviders.tsx

@@ -15,7 +15,7 @@ const BackgroundBlobs = dynamic(() => import("@/components/BackgroundBlobs").cat
 });
 
 const ShaderGradientBackground = dynamic(
-  () => import("./ShaderGradientBackground"),
+  () => import("./ShaderGradientBackground").catch(() => ({ default: () => null })),
   { ssr: false, loading: () => null }
 );
 

app/components/ConsentBanner.tsx

@@ -54,8 +54,6 @@ export default function ConsentBanner() {
             type="button"
             onClick={() => setMinimized(true)}
             className="shrink-0 text-xs text-stone-500 hover:text-stone-900 transition-colors"
-            aria-label="Minimize privacy banner"
-            title="Minimize"
           >
             {s.hide}
           </button>

app/components/ShaderGradientBackground.tsx

@@ -1,9 +1,23 @@
 "use client";
 
-import React from "react";
+import React, { useEffect, useState } from "react";
 import { ShaderGradientCanvas, ShaderGradient } from "@shadergradient/react";
 
 const ShaderGradientBackground = () => {
+  const [supported, setSupported] = useState(true);
+
+  useEffect(() => {
+    try {
+      const canvas = document.createElement("canvas");
+      const gl = canvas.getContext("webgl") || canvas.getContext("experimental-webgl");
+      if (!gl) setSupported(false);
+    } catch {
+      setSupported(false);
+    }
+  }, []);
+
+  if (!supported) return null;
+
   return (
     <div
       style={{

middleware.ts

@@ -88,11 +88,15 @@ export function middleware(request: NextRequest) {
       return addHeaders(request, res);
     }
 
-    // Redirect bare routes to locale-prefixed ones
+    // Add locale prefix: rewrite root path (avoids redirect roundtrip), redirect others
     const preferred = pickLocaleFromHeader(request.headers.get("accept-language"));
-    const redirectTarget =
-      pathname === "/" ? `/${preferred}` : `/${preferred}${pathname}${search || ""}`;
-    responseUrl.pathname = redirectTarget;
+    if (pathname === "/") {
+      responseUrl.pathname = `/${preferred}`;
+      const res = NextResponse.rewrite(responseUrl);
+      res.cookies.set("NEXT_LOCALE", preferred, { path: "/" });
+      return addHeaders(request, res);
+    }
+    responseUrl.pathname = `/${preferred}${pathname}${search || ""}`;
     const res = NextResponse.redirect(responseUrl);
     res.cookies.set("NEXT_LOCALE", preferred, { path: "/" });
     return addHeaders(request, res);

next.config.ts

@@ -34,7 +34,7 @@ const nextConfig: NextConfig = {
   experimental:
     process.env.NODE_ENV === "production"
       ? {
-          optimizePackageImports: ["lucide-react", "framer-motion"],
+          optimizePackageImports: ["lucide-react", "framer-motion", "three", "@react-three/fiber"],
         }
       : {
           // In development, enable webpack build worker for faster builds
@@ -167,12 +167,12 @@ const nextConfig: NextConfig = {
         ],
       },
       {
-        // Only prevent caching for real-time/sensitive API routes
+        // Allow bfcache for n8n routes: use no-cache (revalidate) instead of no-store
         source: "/api/n8n/(.*)",
         headers: [
           {
             key: "Cache-Control",
-            value: "no-store, no-cache, must-revalidate, proxy-revalidate",
+            value: "no-cache, must-revalidate",
           },
         ],
       },