fix: move ShaderGradientBackground dynamic import into client wrapper

next/dynamic with ssr:false is not allowed in Server Components.
Follows existing BackgroundBlobsClient pattern.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/components/ShaderGradientBackgroundClient.tsx

@@ -0,0 +1,16 @@
+"use client";
+
+import React, { useEffect, useState } from "react";
+import ShaderGradientBackground from "./ShaderGradientBackground";
+
+export default function ShaderGradientBackgroundClient() {
+  const [mounted, setMounted] = useState(false);
+
+  useEffect(() => {
+    setMounted(true);
+  }, []);
+
+  if (!mounted) return null;
+
+  return <ShaderGradientBackground />;
+}