refactor: enhance manual chunking in Vite config for better code splitting

webapp/src/lib/download.ts

@@ -0,0 +1,12 @@
+export function downloadBytesAsFile(bytes: Uint8Array, fileName: string, mimeType: string): void {
+  const payload = bytes.slice();
+  const blob = new Blob([payload], { type: mimeType || 'application/octet-stream' });
+  const objectUrl = URL.createObjectURL(blob);
+  const anchor = document.createElement('a');
+  anchor.href = objectUrl;
+  anchor.download = fileName || 'download.bin';
+  document.body.appendChild(anchor);
+  anchor.click();
+  anchor.remove();
+  window.setTimeout(() => URL.revokeObjectURL(objectUrl), 0);
+}