Add WASM verifier loading and asset verification functions

- Introduced loadVerifier function to load the WASM verifier from the server.
- Added verifyAsset function to validate asset data against an expected SHA256 hash using the loaded verifier.
- Ensured compatibility with server-side rendering by checking for the window object.

frontend/src/lib/verifier.ts

@@ -0,0 +1,19 @@
+export async function loadVerifier() {
+	if (typeof window === 'undefined') return null;
+	if ((window as any).verifySHA256) return (window as any).verifySHA256;
+
+	const go = new (window as any).Go();
+	const result = await WebAssembly.instantiateStreaming(
+		fetch('/verifier/verifier.wasm'),
+		go.importObject
+	);
+	go.run(result.instance);
+	return (window as any).verifySHA256;
+}
+
+export async function verifyAsset(data: ArrayBuffer, expectedHash: string): Promise<true | string> {
+	const verify = await loadVerifier();
+	if (!verify) return 'WASM verifier not available';
+
+	return verify(new Uint8Array(data), expectedHash);
+}